# Overheating issue



## 2xtremejc (Aug 21, 2006)

I've got a 1990 Maxima with an overheating problem.

I've flushed the coolant system, re-filled it, nothing.

Replaced the thermostat, helped very little.

Replaced the radiator cap, nothing.

Had the water pump checked, it's fine.

I'm thinking of moving on to replacing the radiator itself next.

Does this sound like a logical progression of troubleshooting this problem? I'm at somewhat of a loss at this point.


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## MyGreenMax94 (Dec 17, 2005)

You may have air pockets in the cooling system....


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## 2xtremejc (Aug 21, 2006)

How do I bleed out any possible air pockets in the cooling system?


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## internetautomart (Mar 8, 2004)

jack up the front end and leave the car running with the radiator cap off


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## richieb (Jun 18, 2006)

Just an odd one!
How are you sure it is overheating?


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## 2xtremejc (Aug 21, 2006)

The same way most folks tell if their car is running hot, the gauge on the dash. It's not 'overheating' as you think of it, it's just running hot. It's better than it was after the things I did to it that are listed above, but it's still running hot.


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## richieb (Jun 18, 2006)

Sometimes the guage tells lies. How far up the guage is the pointer going?
Is it using coolant, or boiling it out at all?
When you switch it off after a run, does it tend to run-on a bit, or clank a bit(Dieseling)
Rads are expensive, if it could be a wiring, guage, or sender problem.
Am not sure whether the sender increases resistance or decreases when warm, i will have to check on mine(Max, May 1990).
My guage sold me a dummy for a while, it was riding high, but the signs of overheating were not there. One day I went out, checked and cleaned the wiring, Guage included, and it has bee ok since then. there is a few small nuts at the back of my guage, they were loose, and mildly oxidised.
The connector to sender was a bit crappy too.
Just a thought, Rads are expensive, and if you have bled the coolant system, heater on hot etc, it may be worth a try for nothing.
I have day off, so off to look at my sender now, car cold, and measure resistance for ya, will post it here in 15 mins or so.


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## richieb (Jun 18, 2006)

Mine Measures 87.1 ohms, connected to car, but battery disconnected, @ 20 degs C.

Do the cooling fans come on at all??


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## richieb (Jun 18, 2006)

Another is...
If my memory serves me right, if the connection to the sender is bad, the guage maxes out, if no cooling fans, no coolant boiling, no odd smells or noises... It could be it.
That little wire is often broken or overlooked!


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## 2xtremejc (Aug 21, 2006)

The gauge gets up to about 10 o'clock(think of a clock face) or ever so slightly higher. The fans come on like normal. 

I'm yet to bleed the cooling system, so I'm gonna try that before I do anything with replacing a radiator.


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## 2xtremejc (Aug 21, 2006)

OK, I finally bled out the coolant system, looks like there was some air pockets in there that worked their way out, I could see them surface and pop with the radiator open. We'll see what happens with the car when it gets driven friday, and I'll re-evaluate at that time.


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