A strange overheating incident

The patient is a 92 with 167k glorious miles. It has a new radiator that was professionally installed about a thousand miles ago or so.

While driving along at 55, I spotted the temp gauge all the way up in the hot position. Just as far as it could possibly go. The suv seemed to be running normally otherwise. When I had a chance I pulled over and popped the hood. There was no steam, no leaks and no unusual "hot" or antifreeze smell. The overflow reservoir had an inch or two of fluid in it. The radiator felt equally hot at the top and the bottom and so did the top and bottom hoses. Turning the engine back on, the belt was turning normally as were all the pulleys and the fan was spinning. I came to the conclusion that I had a gauge or sender problem. Still a long way from home, I decided to risk driving. I was soon on an interstate staying with traffic at about 75. After a while (maybe 1/2 hour) the reading came back down to normal. I did not catch it moving so I don't know if it went down in a single quick move or if it crept down.

Everything has been normal since.

What would make the gauge read high like that? It could be the gauge itself. It could be the sender. It could be a wiring fault. Is there any particular fault that has a history of creating this situation?

Charlie

Reply to
Charlie Bress
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It could be a sticking thermostat. If it is intermittent it can seem very strange.

Watch your gauge closely.

Replacement of the thermostat is a low cost repair.

Soames

Reply to
Hemlock Soames

I considered the thermostat, but decided that if it was stuck that the radiator and hoses would not be equally hot at top an bottom. Also there was no other sign that the engine was any hotter than normal.

Of course, it would not be the first time I was wrong.

Charlie

Reply to
Charlie Bress

It could be if it's an intermitent problem with it being sticky, or working out of range.

I had this happen on my vehicle a couple of months ago. The top radiator hose was hot, so this pointed to it not being the thermostat.

I let the car cool down, then started it up and watched what happened on the temp gauge as the vehicle warmed up. What did happen was that the temp gauge would go almost into the hot area (way higher than it should), then the thermostat would activate, and the temp would come down a little (visible on the gauge), although the gauge was reading way hotter than it should. I was able to get it back to normal range by running the heater full blast.

I determined that while water was flowing in top radiator hose, the thermostat wasn't working correctly. I went ahead and replaced it, and normal operation resumed.

You might try a similar observation, or put the heater on, if it reoccurs, to see if the temp will come down.

Paul

Reply to
Paul Scrutton

If it happens again, turn the heater to full hot and you can check two things, one is, does that make the temp gauge come down. If so, perhaps it WAS running that hot. The other things is, how hot does the air from the heater feel? Since you are trying to judge whether it feels "normal" for a normal temp engine versus "Really hot" for an overheated engine, it might be a little hard to judge so try it first when the engine temp seems normal so you have an idea of how it should feel. If it feels "normal" then perhaps the gauge is wrong. If it feels "'really hot" them, again, maybe the gauge is working right and the engine is overheating.

Another th>The patient is a 92 with 167k glorious miles. It has a new radiator that was

-- Elbridge Gerry, of Massachusetts:

"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789

Reply to
AZGuy

The one time it actually did overheat was a couple of years ago when the fan clutch failed. Then it overheated when it was not being driven fast enough to get decent air flow past the radiator. There was no question of overheating then. There was the spewing of steam and hot water and it was all I could do to get the hood open so that it could start to cool down. None of that with this episode.

Charlie

Reply to
Charlie Bress

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