I just bought my 76 stingray and it is running a little warm. I've changed the waterpump, the radiator, and thermostat. The factory gauge is getting up to 260 or 270. I put in a new guage in the manifold and it still reads around 210 while idleing. Any Ideas??? What should it run at?

 

Welcome to the forum. You need to make sure that all the foam pieces are in place around the rad. There are pieces above and below the rad that seal off to the rad support and hood to make sure all the air is being pulled past the rad. Also, make sure you lip spoiler is in place and not damaged. What condition is the fan shroud in? All these things need to be in place and in good condition to make these Vettes cool properly. Also, make sure somebody didn't put performance pulleys on the water pump, lowering its speed in search of some HP. Good luck.

 

Also make sure that your cooling system is actually full. One trick I heard (of course, after I filled mine) is to park the car with the right front tire up on a curb - that will make the radiator cap the highest point by far. Then fill the system, leave the cap off and start the car. Then continue to top off the coolant. Run the engine up a few thousand rpm's and top it off and put the cap on.

If you have air in your system, the coolant pressure won't rise but the temperature will.

 

Air pockets are NOT NICE. For test purposes only, try drilling a small hole ( 1/8" ) in your T-stat and put a few miles on it that way and see what it does to your temp readings. My '76 stays very Low Temp when I do that. Heck, some guys here at the Ol' Forum run all Summer with a hole in their Stat, but others are dead set against it.......GOOD LUCK :D

 

Some other cooling issues I've dealt with on mine that you might want to check:
Make sure you have an expansion tank and that it is hooked up. You could suck air back in the system otherwise. Also, check your fan clutch. Try to spin it by hand with the engine off and hot. There should be a lot of resistance. Check or replace the radiator cap. Get one rated for at least 16 lbs. Air can be a problem like the others said. If you can't get it all out, yank the T-stat and then try it. You might want to remove it anyhow to see if it might not be opening. Even with a drilled one sometimes it's hard to get the air out.
Peek inside the radiator with the car running. Of course don't open the cap with it hot, better yet, start the car with the cap off when it is cool and let it run until it gets warm. You should see coolant flowing from the tubes. If not your radiator might need to be rodded.
Finally, check your timing and make sure it is not too retarded. Also the carb mixture, make sure it is not too lean.

The high flow pump I installed on mine made the biggest difference though. Dropped temps 30-40 degrees. Don't be too alarmed at temps above 200. Theses babies run hot. The auxilary fan on a 79 doesn't even come on until 238 degrees! The owners manual just says to shut it down if it gets in the red for any length of time. I wasn't used to those kinds of temps when I first got mine either :eek:

 

What high flow pump did you get?

 

Stewart Stage II. I think it's the same as Stage I but mine is aluminium. Bought the drilled T-stat from them too.
http://www.stewartcomponents.com/

 

Welcome to the forum! :steering:

Overheating is a factor on some of the high performance engines. For the 76 model only the L82 350 was available, but even that one was mild at 210HP compared to the other years. Tell us about your vette! If it has the original engine then there will be some numbers stamped into the block on the deck right in front of where the head bolts to the block. The last six numbers stamped on the block there will match the last six numbers of your VIN located on top of the drivers dash near the windshield visible from the outside.

I have the L48 which was rated at 165HP and I have no overheating problems at all even with the air conditioning on max and going to Wide Open Throttle (WOT) lots of times. My original gauge doesn't go over 200ºF. It is possible that your water pump isn't up to snuff. But, a majority of the time it's the engine tuning that is the problem. If the engine isn't running right, then it will run hot.

Check your timing. Check the vacuum hoses and make sure you don't have any leaks. Make sure all the spark plugs are firing. Keep us posted! :flag

 

Thanks for the link isoceles, I added that to my favorites and ordered a catalog.

--marc

 

mck -
Keep in mind, too, that the factory gauges tend to err on the high side - this is very common. I just had a Vette over at the shop last night that the owner thought was running hot. He replaced the sending unit, and the temp gauge showed the car running around 230. I shot the temp with a calibrated infrared sensor and found that the actual engine temp was 188 with a 180 thermostat. Even if you really are running 210, this is not too hot. The C4 Vettes (basically same engine as your C3) typically run 210-230 in traffic and at idle (cooling fans don't even kick on until 230). So don't worry about it until the temp exceeds 240.

 

Check your fan clutch. I just replaced mine and WOW. I was amazed by how much more air is being pushed through, the car has never run this cool.

 

That is probably close to ideal. I think the question is how hot does it go when you are running it?

 

sorry I haven't replied my internet service has been down. Thanks for the help i'll keep you posted.