i have a 1994 camaro z28. ive had my car for about 2 months now but i havnt really had the time to drive it too much because the engine was pissing oil all over the place so i paid $900 and had my front and rear seals replaced, oil sending unit and oil pan. there after i had my transmission completly rebuilt so im just now starting to be able to have my car back.

this problem has been going on since day 1 when i bought the car, but I didn't think it was a big deal but now it's just bugging me.

once the car warms up and all it stays at the 3/4 mark and sometimes stays just a hair shy of red...ill be honest i really dont know much at all about cars...but im guessing ill be learning alot with this one..so my question is what do you think the problem could be here with the engine running that hot?

like i said try to keep the vocabulary simple when you reply, i dont know a whole lot right now but i really dont trust commercial auto shops as of late.

thanks

Kenny

 

OK, do the simple things first:
1. I assume the radiator is full.

2. With the engine running and hot, do a visual check to see if the electric fan is running. If the A/C is on, both fans should be running. As I remember the stock programming has the fan coming on at 200 - 210 degrees (?).

3. If the coolant is at the proper level in the radiator and the electric fan is running, then I would install a new thermostat.

There's a number of other things that can cause the engine to run hot, but I would start with that.

 

Since it is a used car, you have no idea how old the coolant is or if it has the proper water/coolant ratio. I would replace the coolant.

 

Stock stat is 195F and the fans cut on at 225F. Make sure the fans are coming on. They should be if the temp gauge goes as high as you say. If the fans are not coming on, check the fan relay in the under hood fuse box and fans fuse in the fuse panel in the car. If the fans are coming on then go ahead and change the thermostat and coolant, see here for reference http://shbox.com/1/4th_gen_tech2.html#radflush. If that doesn't fix things, it could be-

1) Blown head gasket - hope not, not cheap to have fixed. You can get a test kit from an auto parts store that tests for exhaust gases in the coolant. If exhaust gases are present then a head gasket is blown and exhaust is blowing past the gasket and making it's way into the cooling system heating things up.

2) Clogged radiator - much cheaper to have replaced.

3) Water pump - same as clogged radiator.

4) Bad temp sensor in the drivers head - possible, but not probable.

5) Air in the cooling system - system needs to be burped. See the above reference or do a search on this site on how to do it.

 

Before doing too much else, you might want to reference ricehammer's #5, since it is easy to do and won't cost anything. This is a major cause of the LT-1 overheating and/or running hot. As suggested above, a visual check of the cooling system will tell a lot. Turn the A/C on to ensure that the fans themselves work. If the vehicle is truely running as hot as the gauge says it is, then the electric fans should be on, even with the A/C off; verify that they are. Are the radiator and overflow filled to the proper level? If you are sure the air pockets have been removed and it is still running hot, the next likely candidate is the thermostat. Check out all the suggestions posted here and report back your findings.

 

these motors run way to hot from the factory. you didnt actually give us a number.. what temp is the motor getting to.. because 200+ is considered normal for these motors. if youd like it to be cooler, do these simple things:

flush coolant
get a 165 t-stat
lower temp fan switch
and removing that sound deadening **** on the underside of the hood helps slightly also.
make sure your air dam is in good shape and not broken off or worn down.(thats the plastic piece that directs air to flow over the radiator)

 

flushing the coolant may help, but these motors run hot right from the factory so anything short of swaping the t-stat for a lower one with the corrisponding fan switch isnt really gonna lower it much

 

Nope. The stock thermostat is 180°.

 

New reply to an old Post...

On my new (old) '97 T/A, I've noticed the temp gauge running consistently past 210* and even a bit more when cruising on the highway around 1600 -1800 RPM. It seems to actually run a little cooler off of the highway.

I've flushed the system, bled the air, the fans work when they're suppose to, etc. At this point, I can only assume the stat is the stock 180*. It's not overheating but it does seem to run a bit hotter than I care for. I want to drop in a 160* stat.

My '95 Z has a 160* stat and the fans have been programmed to come on sooner (not sure of the temp). No problems. I seem to remember it also running hot when it was all stock but that was many moons ago.

It's said over and over again that these motors run hot from the factory. But does anyone really know why? Is fuel economy better with a hotter engine? I'm going to keep the T/A stock to get the best MPG I can get out of it. So my real question is would going to the 160* stat help or hurt the gas mileage?

 

Check the cooling system:
* bleed the system
* pressure test the system (look for leaks)
* test the radiator cap
* test the fans
* test the thermostat in a pot of boiling water.
* check for proper coolant mixture.
* check for collapsed hoses

Browse around in here for the various tests:
http://shbox.com/1/4th_gen_tech1.html

 

Shoebox corrected the t'stat issue, and the stock fan programming for his 94 is 226*F for the first fan (or low speed on late 94-model year cars) and 235*F for the 2nd fan (or high speed for the later cars). 95 and newer are all low speed/high speed.

If the air dam under the front bumper is missing, it will run hotter the faster you drive.

The higher combustion chamber temps minimize emissions, and produce better fuel economy. The higher operating temps do not hurt anything mechanically... but they seem to be a major mental block for many people. With the lower temp operation, you may see a small power increase from the reduced inlet air preheat. You aren't going to notice a major change in either the fuel economy or emissions by going to a 160* t'stat.

Before you jump into the lower temp t'stat, why not examine all the elements of the cooling system to insure you aren't putting a band-aid on a significant problem. Put a scanner on it, and verify the operation of the gauge temp sensor in the head and the PCM temp sensor in the water pump, by comparing the gauge reading to the PCM reading. If they are different, one of them is incorrect. Its also very easy to check the temp sensors by meausring the resistance. See Shoebox's website for a "how to". Make the other checks suggested in the posts above.

I don't know if anyone suggested looking through the core to see if it is clogged with leaves, dirt or debris.

 

I was hoping for a reply from Injuneer. Thanks!

As for the front air dam, it's in place and not damaged. As for the temp sensors, etc. that's something I'm going to need to look at. I just got the car a couple of weeks ago so I haven't been too deep into it (yet).

As for the scanner, it threw a code last night so I plan to buy a code scanner today from the AP store. Unless, I can find something quick and fairly inexpensive so I can hook up my laptop?

 

Software/cable for OBD-I LT1's:

http://www.akmcables.com/

http://www.andywhittaker.com/

http://www.ttspowersystems.com/

If you buy a scanner, make sure its not the cheapie Actron ($30) that shorts the pins to flash the codes on the SES light. Will not work after 93, even though the list on the box says it does. If you find a "real" OBD-I scanner, make sure it has the 12-pin OBD-I to 16-pin OBD-II adapter to connect to the ALDL on your 95..... its really sort of screwed up.

Or use Shoebox's method:

http://shbox.com/1/xraycable.jpg

 

Thanks! But my '97 T/A is OBD-II?? I have used Freescan on my '95 Z before (it's a OBD-I w/OBD-II style connector). I have an OBD-II style cable w/RS-232 interface but not sure if it will work with a real OBD-II car. And I don't believe Freescan would work with OBD-II either?

 

Yes.

To validate, you can check the Vehicle Emissions Control Information sticker (engine compartment).