Running Hot

[Joe C]

1996 LT1 72k all stock. As I sat idling for about 15 minutes in 82 degree weather my motor began running hotter than usual. The digital display indicated the temp was 220 and rising. As I got back out on the road it cooled to about 209 as I was driving 65-70 mph. The overflow tank located behind the bumper was about 1/3 full and the coolant in that tank was cool to the touch. The warning lights never indicated that it was over heating...as i initially started the motor i saw it reach and surpass 180 degrees and it just kept getting hotter...if the thermostat had opened should I have seen the temp drop at that point?? ??? is this a thermostat issue ??

[lovehatec4]

Originally Posted by Joe C

1996 LT1 72k all stock. As I sat idling for about 15 minutes in 82 degree weather my motor began running hotter than usual. The digital display indicated the temp was 220 and rising. As I got back out on the road it cooled to about 209 as I was driving 65-70 mph. The overflow tank located behind the bumper was about 1/3 full and the coolant in that tank was cool to the touch. The warning lights never indicated that it was over heating...as i initially started the motor i saw it reach and surpass 180 degrees and it just kept getting hotter...if the thermostat had opened should I have seen the temp drop at that point?? ??? is this a thermostat issue ??

The themostat is'nt an all on or all off devise. They will open as little or as much as needed to regulate coolant temp. When your car is cold, the thermostat barely opens to let in cooler coolant in a little at a time. That means when they open, that they will not open fully untill the temp in the entire system is above the temp rating of the thermostat.The factory thremostat temp is 195 degrees.

These cars run warm from factory and were designed that way to reduce emissions. The fans are computor controlled. On my C4, the main fan won't even turn on until it reaches 226 degrees. On older C4s models, the auxilary fan (in front of radiator) does'nt come on until 236-240 degrees.


As long as you run -37 degree coolant mixture, and your coolant system holds pressure to 18 pounds,you're fine. Thats the reason for the 18 pound cap. Higher presure=higher boil-over temp. If you're not boiling over you're fine. Hope this helps..Let us know.

[lovehatec4]

I forgot to mention,If you have to much coolant say 70-30 ratio, this could cause your car to run warm. Check it cold with a good tester. It should be -37 degrees.

Also,check for blockages in the ducting in front of condenser.These cars are known for sucking debris in the front air duct.

[c4c5specialist]

Hi there,

Your fans will turn on at 228.

This is completely normal, nor is it going to be a durability issue.

However, that being said, 209 at highway speeds is a little high.

I would be looking for debris in the radiator/condensor area.

Alllthebest, c4c5

[Joe C]

I inspected in between the radiator and shroud and it looks like an accumulation of junk to include leaves and hair !!! I have dislodged all of this stuff with compressed air and a brush. I also cleaned the filter that is mounted to the inside of the air duct. There was all kinds of dirt, sand that came from that filter. I hope this solves my problem.... thanks to all that responded.

Joe

[lovehatec4]

Originally Posted by Joe C

I inspected in between the radiator and shroud and it looks like an accumulation of junk to include leaves and hair !!! I have dislodged all of this stuff with compressed air and a brush. I also cleaned the filter that is mounted to the inside of the air duct. There was all kinds of dirt, sand that came from that filter. I hope this solves my problem.... thanks to all that responded.

Joe

Just a reminder, after checking everything discussed including coolant mixture, then try changing your thermostat. It could be sticking but I'm not one to change parts until I've diagnosed the problem.

[NEVRL8T]

Originally Posted by lovehatec4

The factory thremostat temp is 195 degrees.

The factory thermostat is 180*.

[lovehatec4]

As it turns out, NEVRL8T is correct. 180 was factory thermostat temp for 96 LT1. Sorry for the mistake. I just looked it up. Never the less, his car is running warmer than normal and needs a little help. The info I gave him about possible things to check is accurate.

I'm not trying to be arguementative, just trying to help.

Hope I did'nt offend...

[NEVRL8T]

Originally Posted by lovehatec4

As it turns out, NEVRL8T is correct. 180 was factory thermostat temp for 96 LT1. Sorry for the mistake. I just looked it up. Never the less, his car is running warmer than normal and needs a little help. The info I gave him about possible things to check is accurate.

I'm not trying to be arguementative, just trying to help.

Hope I did'nt offend...

You are very correct, the car is running hotter than it should and in no way did you offend me.

[ChuckG]

I took my radiator out a couple years ago. Despite lots of attention, I got a whole grocery bag of crap out from between the radiator and condenser!