Last night I noticed my temp gauge in the red, so I quickly stopped at a gas station and shut off my car. I grabbed a flash light and couldn't find a leak, the overflow resivour was empty. I filled it, and restarted the car, and the gauge went back to normal.

No leaks, & both fans work.

As I was driving I noticed that the higher the rpm, not car speed, the lower the temp would go. 30, 40 50 mph, no difference, but once I turned off overdrive, the rpm jumped over 3000 and the temp dropped fast! 2 seconds from top to normal. In the few miles home, this would repeat every time I would slow down, so I would keep it in low gear. This morning it didn't do it 30 miles to work.

My guess in a sticky thermostat, and once the rpm gets high, the water pressure opens it up. And a rush of cool water runs in and makes the gauge drop fast. I guess.

What do you think?

 

Sounds like either a bad gauge temperature sending unit - right near the engine coolant temp sensor in the upper radiator hose towards the drivers side of the front valve cover

OR

A bad temp gauge in the cluster.

I can't imagine that the temp would drop that suddenly if the thermostat was suddenly opening... but

 

check and see if the radiator fan is spinning. the fan is supposed to be temperature controlled not related to speed or engine rpm but check it anyway

 

The fans were running.

 

at idle speed

 

I guess thats could be it, I just noticed that when I was under the hood, it wasn't very hot. Not more than normal anyway. And I've been under the hood of a car that did actually overheat, and you can feel & smell it.

 

Sounds like an air bubble in the cooling system. Also a bad head gasket can cause this problem (rare in a max).

 

yea i'm thinking air bubble especially since you where out of coolant in the overflow tank. Drain and refill the coolant. See if that fixes the problem.

 

It stopped doing it now, if it does it again I will drain & refill the coolant.

Thanks.

 

if that doesnt work check out all these problems.....

http://forums.maxima.org/showthread.php?t=416416

 

Well. Its not a gauge. Its an air bubble caused by a leak in the water pump seal.

Which means $600 for a new water pump at the dealer.

I would do it my self, but once I told my boss that I would have to take a day off of work, he agreed to pay for it. Sweet. He also bought the car.

 

WTF? Where did you find a boss like that. Dont tell me you are sleeping with him.

 

Can I work your boss.. I mean, "work for" your boss.