Vinscully50

I have a 1986 Camaro IROC Z TPI. With the AC off after my car warms up the temperture gets up to 200-220 on the highway. The car has the air dam, the lower radiator hose was replaced a year ago and it's not collapsing, 180* thermostat was installed in March, water pump is 4 years old and runs like a charm, no noise, no weeping, no coolant leaks anywhere, no bubbles, rad cap is new since March and original ACDelco.

It started doing this about a month ago. I don't know if that's because for the last month the temperature has been 95*F with the heat index close to 110*F? Any ideas?

ULTM8Z

Maybe wait until the weather cools down and see if this setup runs cooler.

hotter weather will reduce the ability of radiator to dissipate heat to the air.

You said this high running temp started within the last month, but your setup has existed in its current state since March.

2knight

iTrader: (1)

Make sure your torque converter is locking up at freeway speed in 4th gear if not it will add more heat to the radiator.

sofakingdom

iTrader: (1)

Is this a problem? If so, how?

Bow_Tied

iTrader: (1)

My stock 87 5.7 runs ~170 according to the stock gauge, only in town/very slow driving does it go to 220 then the secondary fans kicks on. I don't think 200-220 is 'damage level' hot but seems warmer than I'd expect for highway only. I don't have a magic solution for you, sounds like you have checked the basics. Look to see if the rad needs flushed inside and/or out. A new rad cap, which changes the boiling point, not the actual temperature, is good that you have. Have you done any recent work to the car?

Vinscully50

It was running 180* up until recently. It's never ran this hot before. Before the thermostat replacement about 195.

Vinscully50

This has me really curious. A couple of months ago I had the flexplate replaced since it was making noise and it was warped. Could a new or not probably installed flex plate prevent the torque converter from locking up? What are some symptoms? I haven't noticed any slipping of the transmission.

Vinscully50

The coolant was flushed back in March. The radiator looks clean and it looked clean when it was empty back in March.
A few months ago the flexplate was replaced.

sofakingdom

iTrader: (1)

:shrug:

And ... ??

You should know, I made a promise to myself NOT to answer "overheating" threads. But dumba$$ me, I made an exception on your behalf. They're mostly posted by ignorant people that hallucinate they have some sort of superior "knowledge" about temperature that's not available to people with backgrounds in things like physics and engineering, even though their backgrounds are often in nothing more scientific than ... I won't say. I thought you WEREN'T one of those. Sorry. I'll bow out now, and renew my vow.

I'm thinking the flex plate per se is not involved.

2knight

iTrader: (1)

Well if it ran cooler before the thermostat change, could it possibly be a bad thermostat?? I dont know exactly how they work but could it be possible that at sustained higher rpms that the extra coolant flow is pushing a "weak" thermostat partially closed?? Whenever I changed out thermostats I never put the stock style in, I always used the mr. gasket aftermarket ones and 180 degree, and mine never went over 200 degrees and usually ran 190-195 on the highway.

ULTM8Z

What prompted the thermostat change in the first place? If the operating temperature prior to the thermostat change was satisfactory to you, why not just put the old thermostat back in?

BTW, the flex plate has absolutely nothing to do with the converter lock up function.

stron3

iTrader: (2)

It's not unheard of for new parts (including thermostats) to fail a short time later. Just sayin'.

Vinscully50

I put the Mr. Gasket 180 degree thermostat in the car. I was recommended it by a few people. It was running fine up until recently.

Vinscully50

I felt that running at 180* was a better temp compared to 195*. I tossed the old thermostat... I'll probably pull the current one to see if it failed. Throw it in boiling water.

If the heater works, doesn't that mean the thermostat works?

ULTM8Z

I don't believe so. The heater picks up water before the thermostat.

Vinscully50

Alright good news. I have a spare ACDelco 180* thermostat laying around. I remember I brought both at the same time. I was original going to just use the ACDelco but reading threads on this forum some people recommended the Mr. Gasket. I'll pop it in there tomorrow and full around the the Mr. Gasket thermo later.

I did notice that my airdam looks a little bent. It's very lose and has a lot of play. I'm also missing a few bolts. I think it might be time for a replacement.

ULTM8Z

Anything that needs high reliability i typically go with factory over aftermarket. Ignition components, alternators, water pump, etc...

Aftermarket and remans are often times $h!tty quality.

Vinscully50

Yeah. 99% of the parts on my car are ACDeclco. Hoses are Gates, exhaust is Hooker and all gaskets are Fel Pro. The alternator and fan motor are Bosch.

NINÅ

Hawkeye1980

iTrader: (3)

I heard a 170 Degrees thermostat was optimum for the 3rd gen TPI motors? Any thoughts? Mine was running hot, I had to burp the system and I replaced the temperature sensor in the front of the motor. Fans come on as they should and car runs very cool locally and on the highway.

Vinscully50

Update. So the 180* thermostat ended up being wrong, it was a 187* meant for a late model Tahoe/Suburban. So I returned and they gave me another one, I looked at it before I left the autoparts store and it's another 187* meant for the late model tahoe/suburban. So he ordered me another one and again it's a 187* meant for a late model. For whatever reason all of the ACDELCO 12T1D's are another ACDELCO box with a 12T1D sticker stamped over it. How this happened 3 times, I don't know. I ended ordering an ACDelco from Rock Auto. I might also purchase a Gates 180* from the Autoparts store and use that for now.

This morning I did decide to do a flow test of my car. When I started the car, one thing I did notice was my AC Compressor was engaged even though the lever was off inside. It began to squeal. I killed the car, unplugged the compressor and let it idle for 20 minutes. Now I wonder if the AC Compressor was running the entire time and that's what some how shorted the fan controller and has been causing my car to run at 220 even at highway speeds. I'm assuming the AC Compressor always on with out a fan would cause things to get hot?

After about 20 minutes, the car was at 175* (measured by temp gun), there was coolant in the upper and lower radiator hoses. I'm assuming this is a good sign the thermostat is opening? I'll take it for a long drive later and see how she performs.