I'm really hoping sender unit, but I thought I would ask anyway.

1988 Cadillac Cimarron, 2.8 V6. When I bought the car, I found that it unusually ran with the temp gauge around 225 or so all the time. Now it climbs right up to the red zone as the car reaches operating temperature. It will even pass the 260 mark and, of course, the check light will come on now and then.

However, the engine is hot from running and the fan is turning, but there's really nothing else going on here. There's no steaming or boiling, the car performs fine with no loss of acceleration, and the air conditioner will even blow perfectly cold air, none of which has ever been, in my experience, associated with an overheating vehicle.

Of course I get concerned anytime the temperature hand goes above about 2 mm above the halfway mark, but there doesn't seem to be a real problem here. How can I check to be sure my temperature gauge is telling me wild stories? (I can't exactly stick a meat thermometer into the radiator hose.)

have you checked your thermostat lately?


And there aftermarket temp gauges you can try.

Your car is full of coolant right? I've seen cars that overheat from lack of coolant but actually blow cold air out of the vents. If you know somebody who has an infared temp gun you can check your coolant temp with that. Whatever you do I would definently check it out though, your car might run fine at 260 but it doesn't mean it's not doing damage. You can also take out the temp sensor and check it (a repair manual will describe how to for your individual vehicle.)





You can't outrun the radio.

Hook a manual guage up in place of the sending unit and it will tell you for sure what your temp is.

Yes, the car has plenty of coolant in it. I know I faulty water pump can cause some of these symptoms. I plan on having it checked out tomorrow.

It is a huge possibility that your thermostat is stuck, could be stuck partially open. I would suggest changing that first since they're cheap.


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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.

I never did reply to this when I found the problem, but here goes: The service manual lists a whole bunch of tests that can be done to check the thermostat, but I decided it would be easier just to replace it and test it that way. Sure enough, when the temperature barely passed the 220 mark, it stopped, and then fell a little, and hovered pretty well in that area. I'm still not sure that the gauge is perfectly calibrated (Isn't the thermo supposed to be fully open at 212?), but at least the the temperature is staying civil.

Well Dustin Adams , if youre car has been running in the red area in th temp gauge, You might want to keep an eye on youre coolant levels, You cyl HD gaskets or Cyl HD's could get warped. In which could cause a big repair bill down the road.