2000 Oldsmobile Intrigue Cooling problem

3.5L V6
north star (i believe)
2000 Oldsmobile Intrigue

When idling / low RPM the car will overheat, when on the highway the temp seems normal/constant there is a little fluctuation if you slow down and speed up again.

There was/is a small leak in the head gasket that I put some stop leak in (stupid move I now know) but after I put that in the over heating problem started about an hour later I had the system flushed.

The problem still existed and got worse, I replaced the thermostat and it settled down to what I described in the first paragraph.

The fans run and kick up even higher when a temp around 220, I believe, is reached. The pump seems to be working fine because I get plenty of heat in the car. The upper part of the radiator hose is warm and gets hotter when the engine temp goes up and the lower hose is cool.

When at lower speeds the only way that it seem to cool is to rev the engine to about 1800 or 2000 or over then it goes down to a normal operating temperature.

I had a pressure test done and it held.

I also just replaced the radiator to see if it was clogged. It still over heats when RPMs are 1800 - 2000 or below.

Any idea's or things to look at would be appreciated because I'm out of them.

Sunday, December 3rd, 2006 AT 3:53 PM

1 Reply

  • 59 POSTS
Was the coolant very dirty before you replaced it? I don't really understand your putting stop leak in the head gasket. It sounds more like an intake manifold gasket leak.

Anyway I would suggest replacing your water pump or checking the belt if it has a seperate one and verifying that the temperature gauge is actually reading right and that the car is overheating.

You've already replaced the radiator, thermostat, coolant, had it pressure tested, etc.

This is my theory, or I may have heard this somewhere before---The water pump blades are probably worn and not able to pump the coolant at a suffcient volume for the radiator and fan to cool it at the lower speeds. At the higher speeds the pump is able to circulate a higher volume of coolant and along with the fan and the air being drawn in at highway speeds the radiator is able to cool the engine down sufficiently.

Hope that makes sense and that it helps
Good Luck
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Monday, December 4th, 2006 AT 7:48 PM

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