Overheating mystery
 

I have a '92 SVX with a brand new radiator, thermostat, upper and lower hoses and fan switch. Just since a few months ago, I've noticed that it has a tendency to overheat after driving highway speeds. I drive it around town with no trouble, and it usually does fine on the highway as long as I don't slow down. I drove it for an hour and a half a couple weeks ago and the temp gauge stayed right in the middle the whole way...until I slowed down and it started to overheat. I've had the system pressure-checked for leaks which yielded negative results. The only thing I can think of is a bad water pump, but I still have experts telling me that it sounds like either a thermostat or a head gasket. Anybody else have this issue?

Thanks,
Isaiah

Re: Overheating mystery
 

Were you getting the same symptoms before you changed all those parts?
If yes then you have a head gaskets prob.

If not then one of the new parts (the rad or the thermostat) is defective.

Re: Overheating mystery
 

Have you checked the fans to see that they are both working?

Re: Overheating mystery
 

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Sounds like classic head gasket symptoms. Mine did exactly the same thing on my 96 at 125,00 miles.

After slowing down from highway speeds, the temperature gauge starts to rise almost into the red and then starts to go back down to normal.

Head gasket problems are becoming more common as our cars get older It is not a question of mileage, but age.


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Re: Overheating mystery
 

It was doing it last year but I concluded that it was because of my faulty fan switch (the fans weren't coming on). So I replaced it and it seemed to be fine for the rest of the year. Everything worked fine this last winter, too... I just starting having these issues in the last 5 months or less. What puzzles me is that if it *is* a head gasket, then why wouldn't the pressure test catch it?

Re: Overheating mystery
 

Yeah mines doing the same thing.. Tom and I checked for hg problems and ruled them out. The radiator is a year old but its a chinese one and I think that might be what's wrong. Id take the entire radiator out and to a pressure test on it alone. New or not, it might have a leak.

Re: Overheating mystery
 

mine DID the exact same thing .. highway speed fine slow down almost overheat. pressure test...... NOTHING, so spend $$ to tear down guess what HG FAILURE passenger side rear. am not sure why pressure test failed or why compression test / hg test failed twice found it out with continued testing and bubbling in coolant. hope it helps, are you losing coolant ?