I have and 88 K3500 Chevy truck with new AC Delco long block
454 that overheats, specifically when towing on any days
warmer than 50 degrees.
Everything from the grill to the tailpipe has been replaced:
AC condensor, radiator, water pump, engine, intake manifold,
exhaust manifolds, y-pipe, complete exhaust system (less
converter), distributor, ECM and of course all the little
stuff like rad cap, hoses, oxygen sensor, vacuum lines, etc.
I know of three other trucks with this engine, two of which
overheat just like mine, and the other one doesn't. Awhile back, I popped the hood on the truck on a dark night after
a hard run and noticed the exhaust manifolds glowing red hot; hell, they even glow on a 30 degree night after driving
only a few miles at 30-40 mph! The other trucks do it, too.
AC Delco and GM say these engines run hotter that most, but
our overheating problems are ridiculous. Motor home owners
with this engine have problems, too.
My question here at Street Rod Stuff is--what has been your
experience with this engine and it's propensity to run
hot?
I might add that I have dual electric 14" fans, complete
with proper shroud, as fan/fan clutch factory setup was
not doing the job, either.

How hot is it getting? What type and octane of gas are you using? Guess is it is to lean. To much advance? If using gasohol, try gas without. Try a search of the archives here as there are several posts on overheating. There are also articles ( see above) that may help.
--
Mike J

This might sound way to simple but, you didn't mention that you changed the themostat. Just a thought. :)
--
Your "top-less" cruzn buddy, Denise

This sound like a job for Steve Jack.
--
Dick Z

I'm not the brightest bulb in the barrel but you did say that the exhaust manifolds were glowing, didn't you? With everything you've replaced I'd guess that all is well with that stuff. It's the glowing part I'd concern myself with. Never mind others overheating problems, you seem to be completing the burn cycle in the manifold with the exhaust valve open. So I'd really check the timing. I'd also think converter but you said that's gone. What about the mixture, could it be real lean? That might do it. Though, if the exhaust is free flowing I'd look towards the timing. My 2 cents...Frank

To advance or to retard that is the question? Whether it is finished burning to soon or to late. I had this problem when I first bought the car. Changed the timimg and it quit turning the headers red. To lean does make the car get hot at speed. I'm there right. Running cool with 91 octane. Warmed up 20 deg. with 89 octane gasohol. Experimenting with jets and rods now.
--
Mike J

Wow Mike, that's surprising that you'd get that much of a temp swing going from one octane to another. I don't doubt you but I think that what you are saying is that the swing in octane slowed down the flame front. To a point that it, the flame front, could no longer complete combustion in the combustion chamber with the lower octane like it did with the higher octane. That being the case the burn continued, because of this lower octane, after the exhaust valve was open and on into the exhaust manifold. High octane must matter. Stubblefiest, what are you burning, where's the timing set and are we talking stock cam? Frank

I think that the lower octane is more volatile. With the gasohol, from what I have read, you need to go about 10% richer due to the oxygen in the alcohol. I have been watching my temp. gauge real close to see what happens. I have played with timing and jetting. Right now the timing is about 11- 20 -34 This is close to what HRSJ suggested. Runs well on 93 octane.
Chances are my carbs not big enough and I won't get the proper air fuel mix. With the gasohol it was the first time that my exhaust turned brown. But it sure rattles under load.

--
Mike J

Mike, we have an 85 GMC fire truck with a 366 in it and the exhaust manifolds are always red when pumping at a fire. Pumping we run 3200 to 3600 rpm and the water temp runs 190 to 195 constant. It's a good place to warm yer hands during a winter fire. We also burn gasahol in it.
--
Bill Hicks

First time I saw this happen (red headers) was on a friends nova. New hooker headers, burnt a hole in them. Man was he sick.
--
Mike J

Mike, the reason that you are running leaner is that the alcohol has a different specific gravity (not as massive) and therefor changes the mixture to a leaner mix. You will need to rich the mixture to bring the combustion temps in line and alcohol screws up the flamefront timing as well whereas it burns differently. Timing will have to be messed with.....AGAIN?

One quick comment about the last post I made. I remarked that the mechanical fan was not helping.....and I meant the one you chose. The big block fan that was previously mentioned by Lynn is a real air mover, but the dual fans that I mentioned will outperform the mechanical fan. You might want to try the BIG fan, but it will eat up hp.
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

Another idea to consider. Chev makes a heavy duty fan for the 454, and if I remember correctly, it's a 9 blade. When the fan clutch engages, it sounds like an airplane taking off. I had problems with overheating with a 454, changed the fan clutch and blade, problems went away. Before changeover, temps would rise to around 240 when towing a 5thwheel. After the changeover, never got above 200.
--
Lynn Stallbaumer

Thanks for all the responses. Will tell you more history on
this problem now.
This is actually the third engine I've put in the truck.
First one was old and tired when it failed a few weeks
after I bought the truck--I could accept that.
Rebuilt short block overheated from day one. Had put in a
new heavy-duty brass/copper rad as old aluminum one had
many flattened fins and was prone to filling up with bugs
and dirt. No help on overheat under load, or with AC on
anytime outside air went above 85 degrees. Kept telling
the service manager that we had a problem; engine cratered
after one year. Oh, yes, also had correct Stewart high-flow
water pump and their bypass 195 degree thermostat.
Third engine: AC Delco long block. Had radiator re-cored
with 4 rows 1/2 inch tubes, core now almost twice as thick as "heavy-duty" configuration. No relief. Installed 9-bladed plastic fan and new fan clutch (just in case)--made
about 5 degrees difference.
I am running 87 or 89 octane gas--regular unleaded.
Timing is OK, total advance at 2500 rpm is 42 degrees.
5-gas exhaust analyzer shows all numbers perfect.
No vacuum leaks. Fuel pressure is 11 psi. Oxygen sensor
is operating properly. Air diverter valve is too.
All local mechanics are stumped, as we have done everything
and more.
I was amazed to see the exhaust manifolds glowing red, and
so was my mechanic, but non-overheating 454's glow, too.
I can run a 350 hard for many miles, pop the hood and see
no sign of redness in manifolds. I was talking to a GM service manager at a large dealership about my problem, and
he said he had never heard of it. We went through all the
GM service bulletins and such, and before I left he said
"there are 3 or 4 guys running around town with their hoods
off trying to keep their engines cool". So much for "never
heard of it"!
In checking with AC Delco, I have learned that they use
flat topped pistons and get a compression ratio of 8.5:1
Original spec on these engines in a 1-ton truck is 7.9:1
I can't believe that the difference in compression ratio
is enough to cause all of this. I did not ask what
camshaft they use.

Diagnosing towing motors with overheating problems is sometimes difficult because of all of the outside anomolies. The physics can be different as well since they operate in the power mode all the time when towing.

Such things as how much are you towing, does the engine just overheat when going down the road, and so forth.

The red header/manifold issue is something that is common on some motors with heavy loads. When you are using max power to tow, the heat generation is phenomonal! But, this motor could be detonating and you not know it. I would run the max timing in the mid 30s until you know you have licked this issue. If you have an HEI, they are notorious for too much total timing. Install a limiter.

What induction system are you using? Some towing applications take a bit richer mix to keep thing in tact! The timing seems to be a bit too much....I would shoot for mid 30s. Octane will not make a measureable difference here.

First of all what is too hot???? Haven't seen a number yet.

If you want my opinion here it is and I am going to mention all the changes that I think you should make. Let's start with the radiator. The copper brass radiator, even doubled, is not as efficient as a good heavy duty cross flow aluminum with 1.25 inche tubes. The larger tubes will far out perform your current situation because of fins and surface area....maybe as much as 130%. BeCool has great cross flows...for the money. The site here has radiators, but I don't know if they have crossflows and/or 1.25" tubes. Larger tubes means better flow which mean better cooling and greater efficiency. Also, all the fins on the copper brass units are attached with solder....a terrible conductor of heat. These factors are a must to look carefully at.

The fan (mechanical) on the front is probably doing more harm than good. Take it off with the clutch. Use either a Mark 8 fan or Windstar fans (dual), I don't know what your radiator size is...or the fans that you have....a current or wattage will tell me the work capability of the units.....and how are you getting two 14 inchers on..push pull....side by side? Not all fans are created equal, so both of your 14s may not produce that of one good one. The Mark and Winstar fans produce the most CFMs that I have ever come across. CFMs is what you are looking for here.

The water pump is an excellent choice....stick with it. It should perform better with larger tubes as well.

Use only what antifreeze content that you feel you need for minimum protection. Antifreeze is a poor conductor of heat compared with water.

A good insurance policy is a oil cooler...the other liquid! Yes, it too can reduce engine temps 20 degrees if engineered correctly.

If nothing else, check out my cooling forum at www.inccn.net/techforum.htm for more cooling tips.

Hope some of this helps.


--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

"Overheating" here means the gauge hits 250 and the red
Check Gauges Light comes on. It is boiling into the coolant
recovery reservoir at this point.
I pull a 24-foot gooseneck livestock trailer. With just
a horse or two in there, on a 50 degree day recently, I could not drive faster than 30 mph, engine temp 240,
trans temp 210...if I sped up, as the speedo needle went up, so did the engine temp. I could drive into the wind
for 2 miles and the temp would go down to 210; turn around
and go with the wind (the direction I needed to get home)
and temp went right back up to 240+.
I am using a PermaCool Cool Pack II electric fan unit,
2 puller fans, each rated at 2950 cfm.
I agree that the total timing--at 42 degrees--is a little
high; I think spec is 32-38. How does one go about putting
a limiter on this? Computer chip? Or aftermarket device?

Could there be some kind of obstruction in front of the raditator? Or, somehow the air is going over/around? Just another thought,
--
Lynn Stallbaumer

Okay....we are getting somewhere. Good description of what is happening tells me alot. I don't think anything is inherently wrong with the wet part of the cooling system at all. In fact, it is the fan and radiator that are the issue.

For the email that I got this morning that was unsigned, but referred to this post.......the octane level WILL NOT MAKE A DIFFERENCE here and red glowing on tow vehicles and motor homes happens all the time....I have seen many examples. When you are essentially pouring alot of power into the engine and that uses fuel, the waste heat is tremendous! I have even passed motorhomes at night on slight uphill grades in the rain where you can see the reflection from underneath the vehicle from glowing manifolds. On street cars....differing story....differing dynamics at work.

Secondly, as I suspected, the fan pack that you have mentioned in your post is the fans that Perma-cool claims is 2900+ CFMS, with drawing only 9.5 amps each......right? Go look this up it is IMPORTANT! There is no way on this green earth to pull 2900CFMS with only 10 amps!!!!!!!!!!!! I have tested these and others until I am blue in the face and this is the rule of thumb for all high quality and high production fans (call Spal or Derale if ya like to corroborate my take on this)....for every 100CFMs of production at 0" of h2o, with a top of the line designed fan blade/system....you can expect a draw of 1 amp per at 13 vdc. That's it...no exception anywhere to be found. If you do the arithmetic, then the permacool pak will pull 58 amps!!!!! to be somewhere in the working physics of this technology. To figure the reverse......9.5 amps X 2fans will be 19 amps or around 2000CFMS. I have no earthly idea why permacool is claiming these numbers, I hope that this is a misprint or mistake. I have emailed them with no response months ago on this because I am doing a related "Choosing Your Electrical Components" follow up to my cooling ariticles. I briefly talked to a product manager in the fall, but he admitted that he could not explain the differences in their numbers to other manufactures. Still out to lunch to date.

Anyhow....you have to have more CFMs thru the radiator. I suggest the Spal dual 11" with around 2800cfms or the ford Windstar or Mark VIII units for much more. All of these mentioned will blow away what you have....excuse the pun. The Spal will provide another 50% than the current model for example and that is what you need.

An oil cooler won't hurt either.
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

Thanks, HOTRODSRJ, for your detailed responses.

With regard to the Perma Cool fan unit: I had talked to
them after installation, and, of course, they said that it
should be all that I need. Their take on it is that at vehicle speeds over 30-35 mph, the ram air coming through the grill should be sufficient to provide adequate cooling.
(I can idle for an hour, electric fans kicking on and off,
and never get above 220) I do know, however, that the "felt" air coming off of the electric fans no where near compares to the wind storm produced by a mechanical fan hooked direct drive to the water pump...but the noise, and HP/fuel economy loss! (I had fan hooked fast to the
fan clutch last Fall, but never towed anything with the truck before the fan--plastic, 9-bladed, from a '97 7.4L--
disintegrated) Fan clutches are less than reliable, so
that is why I went electric fans...will research Spal, etc.

The engine has a factory oil cooler set-up. Oil cooler in
the radiator was replaced when I had it re-cored.

You had mentioned in a previous post about limiting the
total timing...reducing my present 42 degrees down to 34...
but I am unclear as to how this is accomplished. Sure sounds like something to try.

And as for the glowing, red hot manifolds...these suckers
glow red at 30 mph when it's 30 degrees out, when I am not
loaded or towing. Granted, I have a heavy flat bed on the
truck and weigh 7200 pounds empty, but moving that should not be working that 454 at all at that slow speed.

The 5-gas exhaust analyzer was hooked up and took readings
at idle as well as going down the road at 65 mph, with a
2000 pound load on...air temp was 50 degrees...didn't get
above 230 that day. We want to hook the trailer on, add
some load to it, and repeat the test when it warms up this spring. Also had scan tool hooked up that showed air/fuel
mixture ratio at 14.7:1.

A few comments and observations.

One....the small block would be worse....so never mind the rocket scientist.

Two....I must of missed something....I didn't know that the manifolds where doing this ALL THE TIME. The mixture of 14.7 it too lean for towing and heavy duty (heavy vehicle) use. Ideal is 14.6, for light cruising and that number is richer than your reading and you are NEVER light cruising with your GVW, NEVERMIND WHEN TOWING. I would shoot for 14 or less. There maybe performance packages out there that have a better/richer mixture. The combination of these two tell me that nucleate boiling is happening in or near the cylinders and pushing coolant out. I would boost the radiator cap to at least 20 lbs to retain the coolant.

Ordinarily a sitting and idle test is good for the cooling test for normal engines. However, you are constantly operating in a power mode and this takes lots of fuel and that creates lots of wasted heat....and you have to rid yourself of this. At 35MPH you still need more airflow than you can ram thru the radiator at speed doing some crude heat calculations. The CFMs are not enough with your combo, notwithstanding a possible mixture problem. I know I am suggesting spending more of your $$..but I calculated that a Becool crossflow aluminum radiator with 1.25" tubes, two rows with twin Spals will improve your cooling capacity another 50%!!!! And the Windstars will improve over that.

The timing issue is pretty simple really. I am assuming that you have an HEI, but what kind? Limiting the spring travel and/or heavier springs in the distributor will curtail the advance at high RPMs.

You are right about clutch units for fans for towing ....inconsistant at best. Unfortuneately, your fans are not producing the air that they are advertised to move.

The oil cooler should be outside the radiator...in an external unit with a small powered fan for your application in my opinion. I have fixed several of these factory setups with internal oil coolers here in Hotlanta and the engine temperature dropped significantly.

For information on specs for Spals go to http://spal-usa.com/html/pgtablel.htm for a list. Look up the twin 11" units. You can download a pdf file. Their home web site is www.spal-usa.com and another good site is the www.derale.com site.

If you want more information on the windstar and mark vii fans email me direct and I will send you on your way.




--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

I also wanted to mention that I have a friend with an '89
K3500 who also is having overheating...been through several
radiators and engines...presently has direct drive fan
(spaced within 1 inch of radiator)...he leaves it parked
all summer long. And a nearby GMC truck dealer has a
customer with an '89 GMC 1-ton...you guessed it, overheating
when towing a load...service manager says "stick a 350 in it". Not the answer I am looking for!

I will ask the dealer friday what they every did with the 2 lemon law ones they took back.The mechanical fan is loud but your problem is with the motor.(can those electrics for now and put the mechanical back) it Sounds like you ran into some real parts changers.The manifolds do not glow red unless you have a good load on(motor homes are another story they eat exh manifolds.) I beleive one of the other 89's now has a chevron aluim slider and it is fixed.I knew they did some thing wrong but cant remember if it was cam timing or cats or??? But its not just you and it had nothing to do with the radiator or the fan.Hang in therre for a day more .This dealer was really pissed cause his son even got stuck towing his racecar with it(3 motors).So....they will remember
--
Drive like you stole it !!

Maybe it's time to think Dodge or Ford? I had an '88 K1500 that I bought in '89, had 15k miles. Nice lookin' truck but what a lemon ( a black one at that). Constantly worked on the engine/trans, brakes, and the front seals leaked. Finally found that the brake booster was too small from the factory, and they said I had to pay $100 to have it changed to the correct one. I traded it on a Ford, traded that one on another Ford at 127k four years later, and have 40k on the present one. No probs with either truck to speak of, except for those great Firestone tires.

GM...Mark of Ignorance. (This should start a storm)LOL.

phil
--
One man's treasure is another man's trash.

I'm missing something here? Wasn't it you who has said over and over that, if it is over heating at speed, it is to lean. Thats why I've been playing with mine to see if you were right. Now your changing your story? He's overheating when unloaded also. Just trying to learn something here.
--
Mike J

Mike....haven't changed the story one bit. Most, if not all the time, when you have overheating problems going down the road it's lean. I have even reiterated this issue in my last post when he said he was at a ratio of 14.7 .....too lean for towing or heavy vehicles that run in the power zone all the time.

What did I say that contradicted myself?

And remember, towing and operating under duress is different than just cruising in your roadster down the road.
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

Steve what I was refering to was the A/F mixture, which you addressed after my other post. My thoughts were that if he addressed some of these other things first, it might help in a more cost effective way.
I can see where 220 deg. at idle is also hotter than it should be. If he put a box fan in front while it was idleing and the temp. comes down, I would then say , his fans weren't moving enough air.
I don't know anything about TBI systems other than what I have read and thats very little( was thinking about one for the corvair) but one the the mags did an article recently. It said something about being able to go up an injector size without changing anything else.
I also cann't see, where running empty at a steady throttle, that this would be in power mode.
So this was and is my thoughts, its running to lean for the cooling system to keep up.(fuel or timing)
Hope I didn't get your ire up, just in search of info. I'm probably wrong but thats the way to learn.


Mike Johnson
--
Mike J

Mike....Mike...I don't get my ire up about anything these days except taxes.

This is why I have stated a couple of times that the science of towing an large GVW vehicles is a little different in several departments than "performance oriented" autos. It's just a complete different science from rear end to radiator.

To make my point, even tho this vehicle is "empty"....it still weighs over 7000lbs. That, in and of itself, makes the engine hover in the power mode range just about all the time. Same thing with RVs and such. Have you ever passed one of these trucks (that are empty) or a RV on the highway and you can really hear the motor working even tho they are lumbering along a flat highway. Work = force X distance, so if it's heavier the more work gets done and that is what simplistically is the requirement of the motor to work in that mode. Essentially, the truck "empty" is doing twice the work of a Camaro, let's say, that weighs only 3500lbs. Do you think if that Camaro was towing a 3500lbs boat behind it that the engine would not be working harder to do such. Yes it would. So, that's the reason for my dissertation on towing....

That's all....I meant.
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

I have a 454 in my Studebaker that was rebuilt but apart when I bought it. After putting it together and driving it for 2 years with about 5000 miles on it. i noticed a lower end noise. I pulled the engine and sent it to the machine shop. The crank was pounded and the rods all needed to be resized. The heads had 2 seats that had chips broken out of them. Answer? The oil galleys in the block that feed the crank and rods run low in the block next to the oil pan rail were all cloged up to almost zero. The block was not properly cleaned before I built it the first time. Now with the block all cleaned and clear, I'll be able to tell if my 220 drgree temp at 70 mph will go down to 180 or 190 that I would like to see! I'll let you guys know after I start cruising again. Dave
--
Life's too short to drive an ughly car!

Yep.....that'll do it for sure....sorry to hear the troubles with that big block.

Also, remember that usually when things get hot at speed in a vehicle like yours, the mixture tends to be too lean.

I have an aquaintance, just this year that has been running a 454 in a 55 Belair that was hovering around 230 going down the road too. After some quick questions I invited him over to swill a beer and swap jets and rods on the 750 AFB Edelbrock one hot Saturday afternoon. Started it up...drove to the usual Saturaday cruise and the temp gauge didn't come off the thermostat while crusing.

I hope yours turns out okay.
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

I was on the HAMB this afternoon and they have a great post on timing. Its in the tech post, might be worth looking at.
--
Mike J

Love those 55 Bel Airs...drove a couple of them many a mile!

I am seriously studying your recommendations...have a 20#
radiator cap ordered; not sure where to go to get that timing retarded (would setting base timing back to 0 from
present 5 knock total advance from 42 back to 37?); richer
fuel mixture--get a custom PROM burned for ECM, or install
performance chip? (and whose chip to use??)

I am also not beyond considering a BeCool rad and a Spal fan
unit. Still curious to see what "lostandfound" (I think it
was) found out about lemon law by-backs of trucks that
were equipped like mine--of course, I know I am not in
consideration for such now...

Indeed the ECM chip can cause things to be too lean at times, although it's rare, except in the towing cases.

The timing can be chased, but if you don't have detonation going on, which is the culprit of heat production, then I would leave it. In the case of using the engine during towing and having the timing so high, it can be so noisy under certain circumstances that one never hears the detonation. Do you have a knock sensor? If so, then don't worry.

The BEcool, or Griffin or any quality aluminum big tubed radiator would be a step up in cooling capacity. The fan package to go with is just frosting on the cake.

Just curious, doesn't your Stude have a small opening in the front?
--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

If you mean my Stude, Steve, it's a Hawk and has quite a large "mouth" in front. The radiator support is custom made to seal off the engine bay. The incoming air has to go thru the rad. with no short cuts. The trans cooler is stand alone too. Dave
--
Life's too short to drive an ughly car!

A few more remarks from little ol' me, to HOTRODSRJ:

My engine does not have a knock sensor. I have heard some
detonation from it--last December when I was towing the
gooseneck stock trailer loaded with 9 cows at 1000 pounds
apiece, total load probably 12,000 pounds, and when pulling
a slight grade at 45-50 mph. But with trailer on and
minimal load, and travelling at 60-65 mph, it is hard to
hear if anything is going on, like detonation.

I have done some research on nucleate boiling. By using
a 20 pound radiator cap, the boiling point of the coolant
is only going to be increased 5 or 10 degrees, right?
(What is the 20 pound cap going to do to my heater core,
which, I suspect, is about ready to go anyway?)

And what do you think about waterless cooling? I've been
reading about NPG (non-aqueous propylene glycol) and how
it boils at something like 360 degrees, with a 0 pound
pressure cap. Any advantages for me going this route?

Here is a good article on timing. (over heating)http://www.jalopyjournal.com/ubb/Forum4
--
Mike J

Trying again.
http://www.jalopyjournal.com/ubb/Forum4/HTML/html000011.
--
Mike J

playing.sorry.
www.jalopyjournal.com
--
Mike J

It sounds like you are on the ragged edge of too much timing under load. If you are using an vacuum advanced HEI, then seek a limit device of some sort. Crane makes one available from Summit, or you can make your own internal stop. I have notes on make your own, toooooo long to list here. If the timing is controlled by the ECM, then you will have to seek out a 4x4 chip programmer to customize the mixture and timing in my opinion. '

Nucleate boiling is a phenom that happens under duress and results in high cylinder wall and head temps.....which is formed by hot spots which leads to component damage and coolant out gassing. Nucleate boiling is actually a rare finding in street and performance engines, but can occur on occasion in other applications.

10 PSIG of pressure in the system will raise the corrected water vapor point (boiling point) to 239 degrees F. A twenty pound cap should provide 259 degrees F of protection. Keep in mind....this is pure water now. Add a small amount of antifreeze to it, and it will exceed 270 degrees easily, somewhere that you don't want to be operating. The heater core should be as strong and/or stronger than your radiator. It usually has large tubes with large solder joints...that are stronger. I would not go any further than 22 lbs cap on a conventional radiator. If you have a new fangled aluminum...then up to 26lbs.

The key factor here is that are you losing coolant? If so, try to contain it with the 20+lbs cap. Evans makes the product that you are referring to and even tho it will not boil, it will not cool any better necessarily, but what it does is stays in the system for ever regardless of the heat situation. The newer NPG is better and improved in so far as compatibility is concerned. What they don't tell you is that proplyene glycol only has a specific heat of .33!!! This essentially means that it takes three buckets of NPG to carry away in heat what 1 bucket of water would carry. The engine may not lose coolant, but will actually operate at a higher temperature, depending on what is causing the hot conditions.

Personally, I would fix the system you now have and forgo the expense unless you are always loosing coolant. I would only try the Evans product as a last stand.

Also, I assume that you are running a pretty stock pulley system...right? You could try to find a smaller water pump pulley that is compatible with your system and drive the pump faster. Faster results in more flow and more flow results in more heat transfer.....as long as it is being taken away at the radiator.

--
Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

timing...controlled by ECM

coolant loss...I do have to add a quart about every two weeks--have not determined exactly where it is going, but
I suspect it is sloshing out of the coolant recovery tank
because I do a lot of fairly rough off-road driving as I
pick up large round bales in fields and deliver them to
cattle on pasture. Do not see any external leaks around
engine or radiator, nothing in oil, and 5-gas exhaust
analyzer does not pick up indicators of coolant from
combustion chambers.

Steve, a quick question. I was told by the previous owner that Big Olds runs hot but have not experienced it myself yet. I was told to change the metering rods (1455) and (1464) Step Up Spring Kit (pink or silver springs). Do you think this will help him run cooler? I was also told by another buddy to change to a Robert Shaw Performance T-stat P/N 330-180. What are your thoughts on this? Give it a shot?

--
Your "top-less" cruzn buddy, Denise

Denise,.....the mixture is made up of two differing parts that affect the combination and that is the RODS and JETS. So, to know if changing the jets per se will help, you have to know both..what rods and jets you have in the carb to do it right. The suggested change may indeed richen the mixture (maybe too much), but you may be able to make a rod change without jet changes to accomplish the very same thing without pulling the top of the carb off etal. A rod change is a 1 minute drill whereas you have to remove the top of the carb to make the jet changes. You already know what the jets are apparently, now all you have to do is pull the rods out the top, and read the numbers on the rods....better get the magnifying glasses out! With this information at hand, then you can look at the appropriate chart for your carb (ie..1405. 1406...etc) and move up just on the crusing mode where it is running hot. Just a jet change will affect not only the crusing mode, but will affect the transition circuit at well and may cause other ills.

The spring (the other part of the transition circuit along with the jets and rods that determine mixture on the throttle fly) change to a stiffer spring or silver spring, will richen the transition circuit only. This will not have an effect on just cruising along at all. The transition springs are used to boost mixture during throttle travel and load. If the car is "bogging" when you progressively put your foot into it....this is the first place to start. Most fairly stock cams producing good vacuums will require the stiffer springs than the factory loaded them up with.

Go to my techical links site at www.inccn.net/jackstandslinks.htm and the very first link is for the Edelbrock carb manual that will give you the tables for the mixture....and the recommendations for springs.

The Robert Shaw thermostat is a quality piece, but putting a new thermostat in, unless the old on is faulty, will not improve the cooling of the engine one ioda! It will change the initial opening point, and will establish where the temperature is supposed to hover, but if you have a 185 degree thermostat and you are running 220 hoping to improve cooling and reduce temperatures by putting in a 160 degree thermostat.....simply won't happen. Once the thermostat opens, the rest is up to the total system to cool properly.

Go to my techical forum at www.inccn.net/techforum.htm for more on cooling. There is something there for everyone. The very same pages (with nicely done accouterments...thanks to the good people here at SRS) is in the tech forum here.
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Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

Thanks so much Steve, some things are starting to fall into place now, in my head. You've put it in words that even I can understand. LOL Thanks again. :)))


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Your "top-less" cruzn buddy, Denise

Keep those rods and jets in your pocket. If I meet up with you at a show sometime, I'll let ya fool with my 750 carter. And the beers on me. Dave

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Life's too short to drive an ughly car!

The fun part about changing rods and jets is,you get to go on alot of test drives.(unless you have a dyno)
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Mike J

Flex-a-lite also makes a decent pair of electric fans that may fit your needs. I have a pair of 12" fans, 2500cfm on my Walker radiator in my '40 Buick with a small block, the shroud measurments are approx. 16 x 24 with the two low profile fans in it. It is a perfect fit for my radiator and is only about 3" thick from the rubber around the shroud to the back of each low profile motor on each fan. Works great for me in these southwest Arkansas river bottoms in 105 degree August days running a/c. Can still stay below 200 unless I do a lot idle time. I think they may also have a web page. Check them out, may work for you too.
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I may be getting older, but I refuse to grow up.....

This is just my opinion, try 91 octane gas or higher. If that doesn't work change the timing. If that doesn't work more fuel.
Is this a rebuilt engine? Cast iron heads?
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Mike J

My 1988 C1500 and 1998 K1500 both have a plastic air dam/spoiler under the front bumper. Does your truck have one? If not, is it supposed to have one? ------- It is my understanding that these air dams have a dramatic affect on front air flow. If it is missing, it may be disrupting air flow thru the radiator, or changing the pressure behind the radiator.

1-ton trucks do not have the under-bumper spoiler. They
do have a splash shield underneath the radiator area, to keep water, mud and debris from reaching the crank shaft pulley and throwing the serpentine belt.

How about the airbox/cold air intake...could be blocked up somewhere?? Or are we talking carbureted here?
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Dipstick Streetrod Association Member
If ya aint throwin' sparks ya aint low enough!

Back in 88 when those trucks were new it was a common problem. A bunch of guys bought them and used them to tow there race cars(inclosed 28-32 ft trailer). 3 of them never made 10,000 miles. 3 blown motors cracked heads.2 were bought back by the dealer under the lemon law.I would go find a good dealer that had figured out what the heck happened.its not the first i have heard of this(of 88-89 not the newer stuff).42 degrees total is way to much(dont care what the experts say) Get it down to a safe 34 total for now. If long blocks were installed i would suspect heads and or gaskets also.But glowing manifolds is a NO NO.Timing first.Than go find some one that can run your truck down the road with the new style emmision analizer hooked up layin in the front seat to watch the puter
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Drive like you stole it !!

Cold air intake is clear. Have tried running it with air
duct hose disconnected, even with air cleaner lid turned
upside down to limit restrictions...same results.
These engines were Throttle Body Injected...have installed
two new injectors...same results.

Were they larger or the same?
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Mike J

Dont run it with the air cleaner turned over ,thats a whole bunch of other problems you will get into.Gett the timming cut back. Check to see the 0-2 sensors are working correctly(on the machine)If its run hot or someone used silicone or carb cleaner near them they are junk.
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Drive like you stole it !!

the injectors were the number that the parts list specified.

Sounds to me like your gas/air mixture is too lean, I would also check my ignition timing.

I believe we have covered those things...

We covered them. Did you change anything yet? What temp does your fans come on? Same temp as your thermostat?
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Mike J
Unchartered DSRA Member
If it ain't broke, fix it anyway...

I am now running a 20# pressure cap, still want to change out the 195 stat for a 180. Daytime air temps lately have
been in the 50's, and have been running around empty...no
chance to tow any heavy loads. Engine varies from 180 to
215 at 60-65 mph.

Electric fans come on at 195, via a sensor inserted into
the radiator core just left of center and an inch or two
below the top tank. The turn-on temp is adjustable--from
185 to 220--and I have tried 'em all.

I have checked water pump flow by lowering coolant level in
the radiator, leaving cap off and observing flow from heater
hose back into upper radiator (it's good at idle, though
it foams up at higher rpm--identical results in my '90 1/2-ton 350) so I am reasonably sure that water pump is
doing it's job.

Plans are to load up the gooseneck trailer some warm day and
run another test with 5-gas exhaust analyzer, with engine
operating at 240+. Have been busy on a building project
these last few weeks...

I knew the ECM controlled the timing, but I thought you were on the track to a new chip.

I am still of the opinion that these ECMs are running you too lean. And, the water pump has never been discussed in much length other than it was new. Please tell me it is a high performance aftermarket model....please, the stock ones were junk and the description you made about the water foaming bothers me. Usually, you will see a big increase in flow....but you should not see air in the flow...this is not good. Your pump could be introducing air to the system.

Do something else for experimentation and determination on the pump. Go and get a bottle of water wetter made by RedLine and put one bottle in. See if that stops the frothing at the radiator. The water wetter is a surfactant that changes the coolants surface adheasion properties making for better contact with all surfaces and is harder to introduce air into. It doesn't lower your temperature per se, but will aid in the surface conduction of heat and will help water pick up heat faster (not more)which means you have to get rid of it at the radiator faster too.

Once again I know this is spending your $$, but I have a renewed interest in solving your problem. If you don't have a high performance water pump go and get one. The TuffStuff, Stewarts Components are about the best performing for the money. Now, I would go and purchase the Spal twin 11" or go to the Ford dealer and get a Mark 8 or Windstar fan. My guess is that the twin Spals will be less $$ believe it or not. I would do these things before considering a radiator changeout. This will tell you something about removing heat at the radiator. Reduce the amount of antifreeze too. Just about 15% with the distilled water. This should tell us loads about the system. If we get good results with this and it might get you by, then case closed. If it gets significant results, but yet can't quite keep up, then its a new aluminum crossflow for you to complete the task.

That's all folks.
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Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys

I had installed a Stewart high-flow pump last Spring, when I still had the mechanical fan/fan clutch on the engine, and it lowered the operating temp about 5 degrees.
Unfortunately, that pump was broken when the multi-groove
crankshaft pulley suddenly disintegrated (at about 40 mph)
sending schrapnel everywhere. (that original-equipment
pulley was made of thinner material and shaped differently
than the new replacement pulley--if anyone is running an
OE pulley on a high-mileage engine, change it. after so
many million revolutions with that serpentine belt setup,
it will crack)

I have ordered a new Stewart pump and thermostat. I will
put some water wetter in the cooling system and re-run the flow test. I'm still trying to get answers from GM as to whether the ECM enriches the fuel/air mixture under load. I have talked to Hypertech about their Thermo-master chip, but want to test for fuel/air ratio with a good load behind on a warm day before I plunk down the dollars.

Thanks again for your interest and information.

Ok, HOTROD, I'm going to be taking a side road now...

How about those FAN CLUTCHES that are original equipment?
They engage and pull more air when air coming thru the
radiator reaches a certain temp, but it seems that they
don't stay engaged long, and shouldn't the ram air going
through be sufficient? Again, I am towing a load on a
warm day, here, theoretically.

And another thing...I talked to a guy in Ohio with an
88 C3500 whose original fan clutch ceased being effective
as he was towing in the summer time...says he has been
through 3 new GM fan clutches, and none work the way the
OE did...in fact, my local Chevy dealer service manager
says he has put a new fan clutch or two on his 427 powered
wheat truck, only to overheat while sitting in line to unload on a hot summer day.

In a word, of course, fan clutches are frustrating. How
do you test one to see if it will work...before you install
it, preferably...and are there after-market units that will work consistently and/or last?

In the exact words of Howard Stewart on fan clutches, "Clutch-style fans are inconsistent and we do not recommend their use for any application, if possible."

I happen to concur with this observation and you have just mentioned a bunch of other reasons why!

The themal clutch is very hard to test, if test at all. The theory is that if the fan clutch unit is cool enough (because the radiator air is cool, relatively speaking), the less fan participation that you need. The other type of mechanical fan works on the principle that if you have enough RPMs in the assembly then you must be moving down the road pretty well and don't need cooling, which in your case is false.

In your application, where you are literally on the power curve constantly, the fan is paramount to get to work at top speed. This is why a dual electric unit like the Spals would be preferable all the time. The Mark VIII is a good one too as I have mentioned. But, if you want to try something different, go and affix a big block 17", seven bladed fan WITHOUT the clutch. It will spin all the time which is something that a clutch unit would provide anyway, because of the heat demand, and less the aggrevation of the coupling unit. Those fans at 2500+ really put out the CFMs, but will eat up some power, but like I said, if the clutch is going to keep it in anyway...just bolt it up and make sure it fits the shroud perfectly. Can't loose anything.....? Run the electrics on top of that! That can't hurt either.

Goooooooooooooood luck! Let us know how things are progressing.


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Steve Jack
Engineering & Marketing Technologies
ConceptOne Brackets and Pulleys