I have an 85 vette, 180 deg themostat, 200 deg switch, the themostat is working fine, but the temp creeps up too high. Reaches 220+ cruising. Coolant temp sensor was replaced. Rad. cloged/bad? Also when hot rad. overflow res. not at hot mark.

do you have a clutch fan on it?

it is the stock electric fan. I have had the car a while, and there has never been a problem.

ok...sorry about the fan question...wasnt sure. do you know that the fan is working? how are you certain that the thermostat is working ok?

The fans are working and the thermostat is new. Its a 180 when I was refilling the rad. at ~180 the collant started to flow into the engine.

so it seems that you have proper coolant flow??

I guesss, when the engine is hot shouldn't the overflow res. be at the hot mark? It is not so I' m guessing there is some sort of flow problem. The radiator is full though, but the res. doesn't change when hot. Is it possible that there is an air lock or something?

i know of ways to check into this..but im a bit old school..so my means of diagnosing things are a bit "ghetto"...if youre feeling frisky...you could always remove the rad return hose (with the car cool as not to burn yourself) and see if you have water returning...

but that does make a mess, and if youre going to do that, i would suggest having a bucket handy...perhaps drain the antifreeze out, then try to send water through the system...

did you have some work done that may have caused this, or did it just happen all of a sudden?

I think its flowing ok, but I'll give it a shot. This is kinda dumb question but, Which way do the fans blow. The rad. fan blows twords the engine, which to my knowlege it correct, I also have an aux. fan in front of the rad. Which is blowing away from the rad.(towards the bumper, seems to me to be the wrongway, but I haven't messed with anything around there, Thanks for your help.

they should both guide air through the radiator.

Hi i have seen more than my share of t stats that are bad outta the box, easy check is if car is hot grab top radiator hose and see if it feels hard, if it is t stats not opening wich would over heat. next is ur fan relay could be getting a bit off calibration coming on too late. another is air lock in system vettes are notorious for that. few tips may help ya.

Stat is good , I made the fans com on early 195, How do you go about getting rid of an airlock?

you bleed the system..

yeah bleeding system is like removing all trapped air in the systems high point. leave rad cap loose to start kust turn it so its on but not all the way,theres a half way spot u can feel. then run motorwhen its almost warmed up turn your heater on full blast,this will purge the heater hose lines.after than let cool. remove cap check and fill level replace cap fully,run to temp and open heater up full blast again. vettes like to run around 212 to 220 i think there are some egr sensors that require high temp to operate.

and on a side not, when you go to remove your cap...MAKE SURE it doesnt have pressure behind it...ive seen people get burned severely from anitfreeze...

I have a 1985 and have the same problem of temperature abaove 200. I have a 160 but can not maintain cooler temperatures. I have had other vetts with big blocks without any problems. I will be concentrating on the rad/condensor for blockage. Don't forget that the air is brought in form the street and any object could be sucked in. Other factors to concider is the temp of the trans which is also cooled by the rad. Will let you know my progress.

After a couple of tries and each time being able to and more coolant each time I successfully removed the lock. My front spoiler was really effed up, so I ordered a new one, my head must have been in another place case the one that I had on there wasn't doing any thing, it was all busted up, didn't realize that it so important, thanks for all you help.

I have just taken my rad out and found that it was 1/3 blocked with leaves and a plastic bag. This will also let me clean the condensor for better a/c. This should solve the rising temp. Will let you know.

joe

Theres a few products in summit that are supposed to lower your temps by 40 degrees or so, pretty inexpensive and are added to the normal coolant. Ever try that ?

Thanks for the info. The vet is back together. Things I did. Replaced water pump only because I did not know the age of it(why take a chance). Cleaned out between the condensor and the rad, preasure wash rad and still could not remove all the little stones. Today was 90 degrees her in Virginia Beach and the engine temp. stayed below 190 with a 160 thermostat. Will be trying some addatives to see if I can get it cooler.

joe