Overheating Problems

[PrinceHamlet]

I have an 89 240sx. My wife was driving down the road the other day when the air-conditioning got warm for some reason. She rolled down the windows and kept on trucking. After a few miles, she noticed that the temp gauge was buried in the red. She parked the car and I went to retrieve it later that day. After filling the radiator and checking the oil for water, I drove the car home. The trip was about 40 miles. About half way home, the car again overheated. I allowed the car to cool down and re-filled the radiator and made it home. Not being very mechanically inclined, I started with the thermostat. After replacing it, the car still overheated. My next guess was the radiator cap...no dice. My last shot was the water pump which I replaced but still no go. The car seems to be leaking steam from what might be one of the heater hoses now and I was wondering how much of a task it might be to replace those. They do seem to be pretty far underneath everything. Which way is the best to approach them? From the top or bottom? The car has about 150,000 miles and I figured I would just replace all 3 lines that I can see down there to avoid the problem in the near future.

[quiksilvia]

prolly the top, going from the bottom could be fun with the transmission there, sorry, but why did u replace all those things if it had an obvious leak somewhere? is it the radiator hoses? those are easy.

[Nismo_Freak]

If the overheating happened when the a/c was on then it's simply your aux. electric fan. Verify that the electric fan clicks on when you turn on the a/c.

[PrinceHamlet]

prolly the top, going from the bottom could be fun with the transmission there, sorry, but why did u replace all those things if it had an obvious leak somewhere? is it the radiator hoses? those are easy.

The leak was not obvious at the beginning. At first, there was just a lot of steam and I thought it was escaping from the top radiator hose fitting. What I believe the problem to be is the heater hoses of which there is two and an additional hose that I believe to be just a re-route for an internal water port. I started with the easiest and worked my way up.

[sammy]

look over the radiator very closely also......nissan cheaped out and put a crappy plastic tanked radiator in it, mine had a crack under the overflow hose......hard to notice till i burned the snot out of my hand

[PrinceHamlet]

If the overheating happened when the a/c was on then it's simply your aux. electric fan. Verify that the electric fan clicks on when you turn on the a/c.

The aux fan hasn't worked on this vehicle for a couple of years at least. It wasn't working when I purchased the car.

[PrinceHamlet]

look over the radiator very closely also......nissan cheaped out and put a crappy plastic tanked radiator in it, mine had a crack under the overflow hose......hard to notice till i burned the snot out of my hand

Thanks for the advice. It seems that the problem is coming from down under the throttle body assembly which leads me to believe that it is the heater hose. I have checked and re-checked the top radiator hose and found nothing. I figure to just take the whole thing apart and replace all of those hoses and take my chances.

[Dragon240]

Mine recently broke and it cracked in two places. right along the edge of the plastic tank thing on top behind the black foam **** that is between the radiator and the front cross bar deal and then also cracked about 3in long right on top of the plastic tank directly in front of the upper radiator hose.

[KaDrifter]

My 96 does the same thing but i have 12in fan on it but when i turn the a/c off the temp goes back down. Rad full and no leaks pressured check it thinking the thermo sticking

[PrinceHamlet]

Well gang, it wound up being a hose that was attached to the underside of the manifold. It had a split in it that was about an inch long. I am sure that when the problem started it was much smaller but after getting it hot that many times it grew I'm sure. Thanks everyone for their suggestions and help.