93 240sx Conv Overheating problem

[Seiferliny]

It would over heat for a lil bit but then go back down did it for a lil while but now it isnt doing it anymore.

Doesnt blow smoke or anything must have been just suckin air or something

Think it was an air pocket like you guys said cause its not doing it anymore

Def dont think its a head gasket anymore.


Modified by Seiferliny at 3:56 PM 3/12/2008

[Eikon]

Your symptoms seem very abnormal.. so i'm led to believe that that gauge is reading incorrectly.

My first action would be to replace the temp sensors.

Replace both of them just to be safe. They are not very expensive. There should be a single wire sensor that goes to the dash gauge and a dual wire sensor that goes to the ECU.

I am thinking of several different ideas for what might be wrong. But knowing if you at least have a correct temp reading in the dash would be a great help.

Swing by your dealership and pick up one from the parts counter. Then at least replace the dash sensor.

Then report back to us and we'll figure out where to go from there.

[Eikon]

No, I agree with you. The gauge is not causing the problem. However, it will be much easier to diagnose the problem if we know the gauge is working properly.

I would take the thermostat out and check that area again for any debris or gasket that may be making the thermostat stick.

We'll get it figured out!

[GoinTopless240]

I'm gonna just throw this out there.... did you bleed the system properly using the bleed bolt? Just a thought.. similar symptoms. After you put in a thermostat, you could have gotten some air trapped against it and pressure would cause it not to open and make the car overheat and the heater core would not get hot coolant flow (hence no heat either). Very common oversight on these cars. Not sure if the old "keepin the radiator cap off" trick works with these. Hope you figure it out...

[Eikon]

Air pockets and the lack of being bled properly would be a perfect explanation for what is going on.

Having air pockets would certainly affect your temp readings.

Having air pockets get into or around your heater core would also prevent your heat from working properly.

[biggie]

Almost certain its an air pocket. KAs are nortoriously a pain to get them out. Easiest way is to jack the front end up and use a funnel on top of the rad and fill it with coolant. Squeezing the top hose also seems to help.

[94_240sx]

Almost certain its an air pocket. KAs are nortoriously a pain to get them out. Easiest way is to jack the front end up and use a funnel on top of the rad and fill it with coolant. Squeezing the top hose also seems to help.

Yeah, use 10mm bleeder bolt on the block to let the air out. You have to be patient and wait till the engine gets really hot.

[Eikon]

It's hard for you to hear this.. but relax! Don't worry!

If you don't see any oil in the coolant, coolant in the oil, or strange smoke in the exhaust, you probably don't have an issue with your head gasket.

It's normal to get a little condensation in the exhaust and drip some water out the back.

Take it one step at a time. Start by properly filling and bleeding the coolant system until you are satisfied that you have no more air pockets.

Then report back and we'll go from there.

[BiXLL]

I was having heat problems and I did not want to hear that it could be air in the system. I had never herd of that before and I have been tinkering with cars for over 30 years.

I even went so far as going to my Nissan Tech (I have 2 other new Nissans)and asked him about it. He told me to jack the front of the car up until the back of the car was touching the ground. (as high as possible)Take cap off car and start it up. He then said to just keep adding fluid for about 1/2 hour. It only took about 1 1/2 quarts of antifreeze additional, but all my problems are gone!

[emurger]

The same problem is happening to my 240.My boyfriend's dad is hating my car right now!We found out that the head was cracked and that the head gasket was mostly the cause of the problem. What you could try is jack the front of your car as high as you can and bleed it then. If that doesn't work than you can put a kind of chemical in there(sorry i dont know waht its called) that will hold it for a while, but one day or another it will overheat again just like mine did. With my car having 192K on it I figured its better to replace the engine. If you have questions let me know i'll ask my boyfriend's dad , the one who owns imports plus, he's good.

[S13xCrazy]

I am worried it is the head gasket because the coolant gushes out upon starting and the hoses seem soft i just replaced on and its soft is that bad? Also there is a little bit of water coming from my exhaust but no smoke is coming out the bubbles look like lil clouse of smoke sometimes too

Modified by Seiferliny at 10:09 AM 3/5/2008

The bubbling when you start it tells me that its your headgasket. Maybe I'm wrong, but i have had them go on two of my 240s, and this was the one of the things that happened everytime.

Key things that happened-Gushed out when i started it-No Heat-Would 'gurgle' (coolant boiling) after i turned the car off.

Replacing the head gasket is not hard at all, and you shouldn't be to worried if it is.

Get a compression tester and check each cylinder. If it is your hg and you need tips, feel free to ask. I can answer 99% of your questions im sure.