Hi,

I have a 1997, Z28, Convertible, 30th anniversary Camaro. I bought her "as is" with 62K miles, and a brand new transmission. The guy said she runs warm..well this seemed like an understatement to me..I have had a lot of experiance with overheating cars, as my previous car started wth a radiator leak. After replacing the radiator, it still overheated, but not as quick and it didn't leak. After several tests, and mechanics, and "theories", my fan was rigged so that it ran constantly during ley on power, but I lost my A/C.
Well, seeing as I have had such a sour experiance with overheating cars, I kept my eye on the temperature gage of my Camaro like a hawk. At firts all seemed good, however, when driving in traffic for a while, the temperature gage would crawl up to 210 (halfway), but when I would start moving, it would go back down. I replaced the thermostat, to no avail. Now, as it is getting warmer, the temp. gage will go way past half, all the way to 230 (3/4 and very close to red line). Again, when cars starts moving it cools. I figured it must be one of the fans, and when the car got going air was going in and cooling her off. So, I changed the relays to no avail!
Then, I was driving yesterday, in a TON of traffic, and up goes the temp. I cranked the heat (which my the way NEVER gets cold no matter how hot the cars gets), and was miserable as it was 88 degrees already and I was just waiting to have to pull over. Well, once it got to 230 degrees (3/4 of the way to red), it slowly climbed back to 210. Then slowly back to 230 and again to 210. I wasn't moving at all..Now I am stumped. I got home and let her run for a while in the driveway while watching gage..she never actually "overheated" but would climb to 230 then back to 210 and slowly back to 230 etc..230 is so close to red that it seems to hot...Is she overheating or just running hot? I don't want to crack my head gaskets, HELP!:( PS A/C does NOT work, bu I have not tried charging it yet, as it is a vert and not really hot enough yet to loose any of my already tiny gas mileage!

Usually temperature fluctuations are the cause of a defective stat!.....If it doesn't appear to be overheating, it could be something as simple as a defective temperature sending unit.....It might be time to have the cooling system flushed.....If you're not getting hot air coming out of the heater then the heater core is clogged!

First of all, thanks for the quick reply! I am getting PLENTY of heat when heat is on...it never gets cooler or cold no matter how hot the car is getting. Her system has not been flushed yet though the coollant is clean, not dirty and or rusty etc...She also has a brand new thermostat in, and I checked it to make sure it opened before putting it in (although I checked the old one and that opened too). I am stumped, and do not want to overheat her...I also do not want to pay to have her "figured out", as that is a red flag for mechanics to charge you for crap you don't need, when you "don't know" wahts wrong. If I can do it myself, that is the route I want to go..It seems like a strange pattern of heating, and I am not sure how she is supposed to be acting, and how her temp. gage is supposed to move. Any ideas?

What kind of coolant are you running and what is the mixture of it also??

Sparky,

I did not put the coolant in system, as I have only had her for a few weeks. I checked it though and it seemed clean..I am assuming it is 50/50 and I don't know the brand. Could the brand/ratio really make this much of a difference? It seems like she shouldn't go past 210 (halfway) EVER! And, while she doesn't actually overheat, I am afraid she is running too hot, and don't want to crack her head gaskets :confused:

Angelina, when your car is running, is the temp feel the same on the upper rad. Hose and the lower hose?? ( are both hose''s hot or does one feel alil cooler)??

Im thinking you might have an air pocket in the cooling system??

P.s what temp. Tsat 185-195-200-210?????

For a start, like Bill stated what is the thermostat rating you installed and what does the book call for. I just had a similar issue with a Trans Am that I had for a couple of months. Come to find out it called for and had a 190-195 themostat. Dude I sold it to changed the radiator cap, coolant and stat and brought it back boiling hot in the overflow bottle for me to repair when it didn't do anything to me but stay around 190-210. Check the books for it's ratings and let's proceed from there. :beers:
Chuck

if it doesn't boil over, then it's not technically "overheating".

As said, the books probably suggest a 195°F thermostat so it is going to run hot.

With MAX A/C selected, even if the system does not work, the PCM should turn on both fans. As the PCM coolant temp sensor turns on one fan via the PCM.

With a 12 year old radiator, after a hot run, you should feel or use a temp gun to the backside of the radiator and check the temp of the core to look for either hot spots or cold spots. If cold spots appear, then radiator may need replacing. Might need to replace the radiator anyway to cross off any doubts. Of course, keeping an eye on the coolant reservior level to ensure no loss of coolant and purging of air pockets. This is accomplished by several cold/hot/cold cycles and keeping coolant level at a good point for the system to refill itself as it cools overnight.

Also should check the physical condition of all air dams under the car and bottom engine cover are in tack. These items are placed to prevent hot air from recycling through the radiator again while sitting.

Another point to check as said, is to check the temperature differential between the inlet hose and outlet hose, or the tanks at the hose ports, since temp guns will read the tank surface better than a hose. The minimum differential is 20°F between the two places.

Using another gauge to check the temperature is always helpful and will give some sobering results.

But to reinforce what Derrick has said and I agree, if it ain't boiling over, it ain't overheating - a GM tech told me this statement on my truck when I thought it was running hot. If it ain't puking, don't worry.

I don't exactaly know about 97's but gm sets the fans to come on a 228 degrees, and shut off at 210 so system seems normal. How does it run with a/c on there is a fan overide.

I don't exactaly know about 97's but gm sets the fans to come on a 228 degrees, and shut off at 210 so system seems normal. How does it run with a/c on there is a fan overide.

Bingo

Bingo


Double bingo.

Also, make sure you are running the highest octane fuel you can buy. Those cars are set to run lean and hot to burn off as much emissions as possible. Those cars have almost nowhere for the heat to go when they're sitting still. I used to have an '01 Z28.

If you're that worried about it, go on eBay and buy a used Hypertech III programmer and a low temperature thermostat. Then use the tuning feature of the Hypertech only to tell it that you have a low temperature thermostat and also change the fan on/off settings. You do not have to use the power tuning if you don't want to.

I ran my supercharged S10 with a 160 degree thermostat like that for a while and it would not budge past 160 in any temp with the A/C on. The power tuning in the Hypertech is basically just spark advance which is a big no-no on a supercharged engine. I just used the 160 degree thermostat setting, speedometer calibration for my tires and gears, and increased speed limiter functions. I finally bought a used ECM off ebay and sent it to a Vortec guru in Michigan to program it for my mods and am running that one with my stock ECM kept as a spare.

Here is the link if you want to go that route: http://www.pcmforless.com/

My truck now runs better than ever with 108k on the clock and gets 23+ mpg highway which I haven't gotten since it was stock with 3.08 gears and I have 3.42's now.