CA1992C4

My wife took our 1992 C4 for a 30 mile ride on the freeway to visit friends last night, and the tempature got hotter than ever before. The car showed a tempature of 239 and she pulled over and called me to see if that was high. I told her it was, and she drove the car back home with the car running between 239 to 245.

The car has never run that hot before, and I have only seen it in the upper 220’s in stop and go traffic before the fans kick on.

My first guess is the thermostat might be stuck, and is not opening up all the way, as the car has 130,000 miles on it and I have no idea if it has been replaced recently.

I need to do somthing before driving it again - what other things should I look for?

Whaleman

I guess first thing is to open the radiator cap and see if low on coolant. Second would be to check the radiator to see if you sucked up a big plastic bag or something. Dan

CA1992C4

I checked the coolant and it’s full. I checked for a plastic bag and the radiator was clear.

I bought a new thermostat and coolant, so I’ll put the new one in and see if that helps.

Whaleman

I was running 210 in my 96 and flushed completely, Pulled and changed the knock sensors, flushed the heater core and filled with Prestone green long life and installed a 180 thermostat from Ecklers. I now run 194 when moving. Maybe 208 stopped for a while. Dan

billschroeder5842

Well you need to check BETWEEN the radiator and condenser. You will need to take off your radiator shroud and take a look. With 130k you may have no idea what got sucked up, and in between....

I though my radiator was clean too.... until....

Whaleman

Bill, On my 96 the shroud is cut around the freon lines to the condenser. I can look in to see the face of the radiator. I can also use my leaf blower through this area to get loose stuff out. The cuts seem factory. Is this factory for a 96 and does this not exist for earlier? Dan

Whaleman

You can see the open area around the freon lines. Dan

billschroeder5842

Dan- you are right on the 96 as it looks like you can put an eyeball on the situation.

On my 89 and 91ZR1, you have to pop the shroud off. Maybe the engineers got smarter in the later years!

Whaleman

I have always wondered if I loose air pressure through this kinda largish opening. I know I could cut some flat black plastic and make the open area maybe 5% of what it is now and secure with easy to remove screws. Dan

CA1992C4

I installed a new 180° thermostat this morning and took the car out for a 15 minute ride. The operating temperature fluctuated between 195 - 197.

When I inspected the old thermostat, I could see some crud on it. It looked like whoever put the last thermostat in used gasket sealer. I managed to remove the thermostat, but the rubber gasket was stuck in the waterpump, and was real pain to remove.

I will take it for a longer ride today, with some freeway driving, and in some stop and go traffic to see if heats up again.

Thanks to everyone that offered advice!

Cool Runnings

Thinking 96 is same as 92.