I've posted a few times before regarding my car's cooling problem, mostly to gather some feedback on how other forum members' cars behaved in hot weather. Today while driving the car I decided to push the limits, run the AC on full/recirculate, and see what would happen. Now my cooling problem is actually an overheating problem so I'm bringing this topic back up to help troubleshoot my problem and come up with possible solutions.

Within 30 minutes of around-town cruising with the AC on full my coolant temps got up to 240 degrees and some of my coolant (which was heavier on the water side than on the coolant side) boiled out of reservoir. The ambient temp was about 100 degrees F and I think my coolant would have gotten hotter but I turned off the car after noticing that it was losing coolant. I topped off the car with 50/50 and proceeded to the rest of my experiment: cruising around for a while with no AC to see where my temps would get to. I managed to get the coolant up to 210 degrees. All of this is being done with a 160 thermostat and the fan turn on temps set to 180 and 185. The radiator is also lowered to accomodate my supercharger.

I'm trying to get some troubleshooting tips to determine exactly where my problem lies. I've checked both of my fans and they both turn on. They seem to be pushing quite a bit of air too. I swapped out my stock radiator with a Dewitt's radiator (almost twice as big) and I still have the heating issue (it just takes longer to heat up due to the increased coolant capacity). I've also tried the obvious which is checking the condensor and radiator for debris and pressure washing it to remove any dirt that may have accumulated -- no dice on that. I do have my center air dam in place but the side air dams were removed to help the car clear ramps and lifts. I am also running the Z06 screens with the fog light surrounds removed to improve under-the-hood cooling.

Is it somehow possible that the fans are not pushing as hard as they should? Are there other high-powered alternatives out there that would move more CFMs than the stock fans but fit in the stock fan assembly? Are there other things I should look out for or check? None of my coolant hoses appear to be kinked.

Help!

 

Is the thermostat actually opening up at 160 or anywhere above that temp? Cook it in a pan of water with a thermometer to be sure of the exact temperature that it opens. Just an idea...
Good luck...Bill

 

You never know but is the thermostat put in correctly, not backwards? It may not be opening properly, it could be defective.

Good luck

TTT

 

but before you pull the thermostat use a piece of paper behind each fan to make sure they are actually operating

 

I know it may sound lame, but what about the water pump? Could it be failing? Maybe switching to the Maziere electric pump would function better in FL, where a constant flow will cool more efficiently.

 

Thanks guys for the suggestions. Using EFILive, I am able to turn on both fans from my laptop without the car getting up to temperature, so I know they are working from that perspective. I have also verified the fan temp settings in LS1Edit. What I have not done yet is get the car hot, then get it on a lift or ramps to check both fans. I will try that as well as checking the thermostat.

DrCoffee, I have been thinking about getting a Mezierre. The only things I'm not a big fan of is (a) the price and (b) the fact that now my water pump would have a more finite lifespan than it used to. Still, if it solves my problem, I'll be a happy customer.

Any other thoughts/suggestions?

 

Buy a Be-Cool radiator
My car runs at 195 with a 192 t-stat in 108 degree weather at 20 to 95 mph.

 

Thanks for the suggestion. I recently purchased a Dewitt's radiator which is supposed to get similar temps. The unit itself is about twice the size of the stocker. While this did help keep the temps from rising quickly, they still rise. So I am thinking that the problem is most likely outside of the radiator itself...

 

supercharged eh
I'd check :
See if it's tuned correctly , it maybe running lean.
bad t-stat
restricted exhaust
bad head gasket

I'd post in here also : http://forums.corvetteforum.com/forumdisplay.php?f=86

 

I also have a Doug Dewitt's and I am cranking out 500 HP at the flywheel. Our heat here in Dallas is high as is yours. I have a 180 degree thermostat, an automatoc trans and a 2800 stall converter. All of this makes lots of heat. I am having no trouble keeping my engine cool. Today we were at 92 degrees, cool for us, and my temps are 178 for the engine and 196 for the trans. City driving, air off.

The fact that it takes longer to heat up the car now tends to make me believe that the radiator works just fine. On top of that at highway speeds the fans are factored out. You did not say how many miles are on the car. It may be that the water pump is not working properly. Does it get hot at crusing speeds on the freeway? If not it may be the fans.

Is it possible that somewhere within the engine the flow of water is being restricted?

If I were you I would replace the water pump at this point. I would also drain the system and flush the engines (not the radiator) cooling system in the reverse direction. Normally distilled water is used in the cooling system, are you using that? If it came down to it I would use a garden hose to reverse flush the engine if I had to.

Its easy to check airflow, just look for obstructions, besides if you recently put the Dewitts in you had it all apart so you know if airflow is blocked.

If air is moving through the only thing left is coolant. Is it flowing properly? My bet is its not.

All of this assumes (thats dangerious) that the rest of your engine is working properly, as in no head gasket leaks.

 

The Dewitt's radiator is just as good.
I have installed 12" Spal fans in the stock shroud. They pull some SERIOUS air! The Evans high pressure pump and their waterless coolant is supposed to work well too.
You might check to see if you have combustion gasses in the cooling system. (blown or leaking head gasket) That will heat the water up, no matter what size radiator. Good luck with it!

 

Since it's supercharged the tune is actually a little richer than it ordinarily would be... gotta keep the motor from predetonating. I've had this cooling issue across two different exhausts (Corsa Pace Car and Z06 Ti) and the motor is fresh -- a 383 with less than 2000 miles on it. Cylinder heads were replaced at the same time the motor was pulled, and beyond that I also had this problem on my stock motor with stock heads.

At highway speeds, cruising at 2000RPM or so, my temps are nice and low, even in the hot weather with the AC on high... somewhere around 180ish. This leads me to believe that it could be the fans as was suggested above, but oddly both fans do turn on and they are pushing quite a bit of air out toward the motor. I don't have a frame of reference to say whether or not they're moving air like they should but I was surprised by how much air they moved when I tested the fans using EFILive.

 

Thanks for the help Andy. I've never heard of the Evans water pump or their coolant before so I'll dig into that a little more. I think I will try the Spal fans first, though as the fans are one of the few commonalities between my car when it first began exhibiting the problem and my car now.

I was actually going to give you a call today but I figured I'd dig around on the forum first before bothering you.

 

Shouldn't your fans be "Pulling" rather than "Pushing" the air?

 

This may be way too simple but have you checked up in the front of the radiator for debri? It's a great trap for anything that can blow in. I have even seen a plastic shopping bag stuck up there in one car!

 

You are correct -- a mistake on my behalf. The fans are in fact pulling the air toward the motor.