Overheating problem

Is your coolant really hot? Are you losing coolant (boil over)? Gauges are mechanical devices which may not be correct. Yours connects to a sensor in the coolant stream. If you are not losing coolant use an IR gun or a touch type thermometer and see how hot the coolant is. Your cooling fans should turn on low speed at 199 degrees and go to high at

crispycritter wrote:

I don't know this car but there may be 2 separate temp sensors - one for the gauge sand one for the computer. So there are several items not on his list that should be checked to see if they are working correctly. =

But it seems unlikely that will be the source of the problem. If we can assume that the OP has described the problem correctly then it seems he can drive around all day in town (stop and go traffic) without it overheating. That indicates that all of the sensors gauges and fans are working as they should. It's seems oily when he drives at highway speeds for more than 12 mins. that it overheats. The fan doesn't add much to the cooling capacity at 65 mph.

So I would look for something that is restricting the air flow or coolant flow at high speed. Did he forget to remove that piece of cardboard he stuck in the grille when it was -20=B0 last winter? Maybe th= e suction side radiator hose is collapsing at high speed. Also late ignition timing coupled with high speed can cause excess heat generation. =

-jim

It's hard to demonstrate that it doesn't overheat due to excessive city driving, because I do so little. Most is done on the freeway. But once off the freeway, the little bit of city driving I do does cause the temp to cool down to about half way (although still higher than what one would expect).

As for any type of obstruction, e.g. cardboard in the grille, I just bought the car last month (from a private seller), and in that time I haven't added any jury-rigged devices, and I haven't discovered anything that might have been installed by the previous owner during all the tests and replacements thus far.

Interesting note on the ignition. I'll have that checked too. Thanks.

Re: the previous poster, thanks for the tip. No I don't seem to be losing coolant. I'll see if I can get a temperature reading on the coolant while it's running hot.

Did you reverse flush the block with a garden hose or some such when you did these replacements?

Before doing anything more you need to do a cylinder leakdown test on all cylinders and/or check for the presense of exhaust byproducts in the coolant, there are test strips for this, to eliminate a failed head gasket.

I am not sure why you think a failed head gasket would always result in steam out of the exhaust pipe.

Ted

So you don't actually know that it is overheating? For all you know half way is right where it is supposed to be. I would still be concerned a little about it going up when driving at highway speeds, but the gauge could be very sensitive in that temperature band so it's possible that could be just a few degrees elevated.

-jim