Over heating

Hey problemenko,

You are not alone, I have the exact same problem and I have been chasing it for 2 years. So far, here is what I know/have done:

- I've recored the stock 3 core radiator
- Replaced all of the radiator/shroud seals, the shroud is correct and in place.
- Replaced all the hoses (lower has no spring) and flushed the system. (fluid color is excellent)
- Fan clutch was not replaced but is not leaking and is very stiff.
- Just replace the water pump with a good aluminum aftermarket pump
- Just replaced the thermostat with a 160 degree model.

I've not been able to thoroughly test the new waterpump and thermostat since it hasn't been above 75 degrees here. So far the 35 degree thermostat drop has equated to an overall temp drop of about 20 degrees. I do not have the radiator to hood seal in place and my 1 inch wide lower spoiler is rather flimsy. Other than that, I don't know what else to try other than the water wetter and thermostat with extra holes in it.

I'm running high compression, high octane, and a large cam. My temp starts to climb after hard acceleration (goes away quickly) and driving more than 10 minutes at 2500 rpms or greater.

Let me know if you come up with any solutions.

I called DeWitts and I'm thinking of parting with a fair amount of cash when they return from Bloomington Gold. In the meantime I'll try another thermostat and flush. The symptoms are the same with my 79 as yours (ricknhis69). Later.....

Problemenko,

Have had exactly the same problem as you with my '73 small block. Everything was new when car was restored. Radiator was flushed and pressure tested but not recored.Car continues to heat up when accelerated above 2500 rpm also. Am going to have the radiator recored but in the meantime, tried a 12 0z. bottle of "Water Wetter" and it lowered the temp to about 200 where it stayed regardless of how fast I ran it. I would recommend you try it. Bill, '73 REDVETTE

Bill, Thanks for the tip. I'll try the water wetter this week. I had the car out on Saturday after I drained and flushed it. Same problem once again. The temp raises above 220 for very brief periods but never more than around 225. A few bucks for the water wetter is worth a try. Fran

Problemenko,

Here is the latest. It STILL hasn't been over 80 degrees here (this is the most ridiculous summer ever) so I haven't had an opportunity to test things thoroughly although so far there seems to be an improvement. Last weekend I ran 20 miles with the A/C on at 70mph and the temperature did climb to 220 but it did not go any higher. Previously it would climb above this without the A/C on. It was only 80 degrees though so time will tell. Who knows if the gauge is right but whats important here is that the temp has stabilized. I'm running a 160 degree thermostat, which I don't prefer since it can be too cool in cool weather. Once I get things under control I will try stepping up to a 185. If you recall I also changed water pumps so unfortunately I can't tell you which one made the difference. By the way, on the subject of replacement water pumps, I highly recommend a high quality aluminum pump. Prices run from $75 to $175. Edelbrock seems to run on the high end (I don't have one of these, mine came from Jegs) but I have heard several people tell me that Edelbrock made a world of difference on their C3. Just don't buy a chrome one, its just a basic steel pump thats been polished and chromed and half of them are defective right out of the box. The one I replaced was new (from previous owner) with a bent shaft. Whatever you buy, check the pulley clearance before you are commited.

Someone at a car show recently just had an interesting theory. He said that he remembers that chevy had some problems with the passages in the cylinder heads lining up with the passages in the block which amounted to a flow restriction. It's also possible that there is a partial obstruction somewhere in the block of some other kind. I know my block is clean since it was recently rebuilt but the misalignment of the passages seems like an interesting idea. It would certainly explain the symptoms.

No matter what though, for the price, I'd replace that thermostat asap.

Good luck, and keep me posted!!



|UPDATED|7/15/2004 9:00:00 PM (AZT)|/UPDATED|

rickinhis69, Thanks for the tip. I'll pick up a new thermostat today and give it a try this weekend. I'll post the results.

For the age of our cars I'am sure the radiators have been replaced or recored at least a couple of times,the aftermarket replacements or cores might not be the same as originals even thought the exterior demensions are the same, whats important is the amount of rows and fins per inch,the less fins per inch the less heat is expelled, not all radiators are created equal.

Anips-

I agree, not all radiators are created equal. However, in my case, my recore has more fins per inch and is better assembled than the original. I really believe that a well made 3 core radiator should easily handle the heat from a small block.

I am new at this but when I got my 80 the previous owner had put in a cheap upper hose. The bends were not right and it was pinching just slightly at one of the bends. Changed it out and the temp went right down.

It's been a while since I've read the thread and it looks like just about everything has been covered, except no one has said anything about checking the condensor for debris, For the rubber bumper cars a trick is to get out the ole hack saw blade and file and open the air intake holes on the lower valance, my cooling system consist of a 4 row brass radiator, alum.water pump,weather strip in place, 25lb.cap, 25-75 antifreeze-water ratio, one pt. prestone cooling system lubricant, 160 thermostate, clutch fan, no water wetter, it idles at 180 all day,runs just under 200 all day at 100 degrees weather temp, I read that all water wetter is is some sort of none sudsing soap, and some people have had trouble with it, thats why I don't run it,.... "Hey honey,would you please draw the bath water for me, and use that new exspensive
soap I got at auto parts today, its the red stuff in the little bottle in the geerage"

|UPDATED|8/6/2004 10:51:35 PM (AZT)|/UPDATED|