NEED HELP, Engine is heating up!!!!!!!!!!!!! PLEASE Help

[2fst4u]

Hi Guys I am having problem with my 1995 automatic 240sx. It starts and runs fine but my temperature gauge reads that it is over heating. I know that my car did it once before about two months ago then went back to normal after I turn it off for 10 minutes and no problems till now. I was driving my car 3 days ago and everything was fine. I then turn on my Air condition then the car started to over heat. I turn off the car immediatly. Waited about 5 minutes then started to drive and everything was fine. Drove home approx 13 km no heating up and A/c was off. I went home to check my coolant and the rad was full except the over flow tank was empty, all belts where still on, but I know sometimes my belt squeek, if that makes a difference or not. Later that night I went to the store to get some milk and about 5 minutes of driving the gauge read that it was over heating and so I turned back home. Next day I change the termostat and the thermostat gasket. Drove it for about 5 minutes then the temperature gauge was reading HOT. So I am not sure what else it could be. Could it possibly be a water pump? How do I know if my water pump is good or not. Also after I pulled it back into my garage, I noticed the top rad hose was hot and the bottom hose (connected to the thermostat) was cool. I bleeded the bubbles out and still same problem. Just cause of curiousity, I put my old thermo stat into boiling water and it open and closed properly so I know it wasnt the problem in the first place. One more thing I should add, I talk to a friend of mine an he said to check if the water pump is working properly, take the rad cap off and when I reving the engine, the coolant level should go down and when releasing the pedal the coolant should raise back to normal level. I did that but the opposite happen. When I rev the engine, the coolant flow over the rad cap spot. When releasing the pedal the fluid goes back to normal. What does this mean? How else would I check if my water pump is working? I hope it is not a head gasket. ANY ADVICE WOULD HELP THANK YOU SO MUCH

[w1ngzer0]

Well, if you had a head gasket leak you would see burning coolant comming out of your tail or smell it. Also is your radiator fan running?

I don't know how to check if your water pump is working or not. Mabie you can see the external wheel turn or not?

[240marcuSX]

water pumps are cheap, if you think its that, go ahead and replace it, and the thermostat.

I got both today from NAPA for $48.00

[Oatmealman]

He already replaced the thermostat.It could be the fan clutch but i doubt that.My money would be on a leaky head gasket,or possibly a cracked block

[Mr1der]

check for coolant in the oil...it'll make the oil look kinda milky....

check to see if your radiator fan is pulling air at idle too.

[Dattebayo]

Why is this in gen chat again?

Go to 240 tech or gen.

[ddgsxr504]

Man I can't tell you how many of these threads I see about S14's over heating (supposedly).

It usually turns out to be something like your (RADIATOR CAP). Start there and then get back to us.

[benemorius]

It's pretty clear that your radiator is clogging if the top is hot and the bottom is cool. The bottom shouldn't be quite as hot as the top, but it shouldn't be non-hot either.