Overheating---I think

[SHO91+]

About three weks ago I saw my temperature guage riding directly on the "m" while driving on the highway. While this may not seem unusual to some,this car, which I purchased new in 1991 has always been what I would consider a cold runner. The normal position of the temp. guage has always been on the "L" and seldom has ever been higher than mid range. In fact, in the winter I patiently wait to finally get some decent warmth from the heater. This higher than expected reading of course prompted me to do something, so I replaced the thermostat (195) and the guage sending unit. This resulted in no change and I need some advice on what else to be looking at. The cooling fan does work, and cycles but at what I feel are higher readings than before this issue popped up. The car has 132k miles, water pump was replaced at 82k and the current radiator 16k miles ago. Nothing is leaking and the car seems to run O.K., but when opening the hood now there seems to be more heat from the motor (or maybe I want it to). I have a new SHO Source equal length pipe to put on, replacing a very old SHOShop unit. Was thinking I could have a cat. problem making the motor run hot. Anyway folks, what do you think??

 

[sperold]

I think if you are nervous about it, you could install a 180 degree thermostat.
Do you always have the AC on in the summer? Does anything change if you shut it off?
Check in front of the AC condenser and between it and the radiator for anything blocking airflow.
It could be something as simple as the gauge reading differently.
And as far as changing the sending unit, remember there are 2, one for the gauge, and one for your computer, so there is a slight chance you changed the one for the computer.

 

[rubydist]

it sounds completely normal to me.

 

[Irish Pride]

My 91 is exactly how you describe a cool runner. Two years ago I noticed it running warmer than normal so I completely flushed the system and changed the T-stat. After that it still was running warmer than normal and I was still concerned. Come to find out the hose that runs from the radiator to the overflow bottle had gotten clogged. Once I discovered that and cleared the hose it started running back where it used to. In my opinion, these cars are pretty predictable. If you see a change then something probably needs to be addressed. Probably nothing major though.

 

[jimtash]

Make sure nothing is blocking the airflow.

 

[Off Road SHO]

If no heat in passenger cabin, make sure BOTH hoses that feed it with coolant get hot at the same time. If they don't, the heater core is plugged up with sediment.

And get yourself one of those infrared temp sensors. Worth their weight in sleepless nights.

Tom

 

[tery]

And lightly power wash the radiator, I was shocked at the amount of dirt that came out from between the heat cooling fins when I washed out my radiator, but don't hit it too hard with the water if it's old, I learned that the hard way too. Didn't make any leaks, but you could see the water start to smash the fins since it is so thin like aluminum foil, grand cooler a bit after the cleaning.