Overheating problems – need help please !!!!!

[juno]

Need help with my 240xs.

Couple of weeks ago my car started to overheat. I discovered that the leaking radiator was the cultrate behind it. After driving the car for a week and constantly replenishing the radiator water I was able to get some money and purchase a new radiator.

After replacing the radiator I discovered more problems, my water pump was leaking some fluid too. I replaced the water pump and the thermostat (from AutoZone).

Now it looks like nothing is leaking, but my car is still overheating. Some of my observations are:

The car overheats when I drive it for about 30 seconds but works fine on idle mode. Another think I have noticed is that the top hose that comes from the radiator is under extreme pressure when the car overheats.

I have no idea what to trouble shoot next, any advice would be greatly appreciated. Thank you in advance,

-J

[orestes]

wow same shit happened to me awhile back. i think i remember reading somewhere that there sometimes can be problems with air being trapped in the radiator on 240's and that its a good idea to have the front jacked up when you put coolant in so it sits differently and may make the air bubble out. other than that id say maybe take it to nissan dealer? or if you know any real good mechanics have them look.

other than that double check the water pump? i dont know man

[nissanfanatic]

When filling the radiator, make sure you have the temp setting for climate control on the highest heat setting. Then commence in filling the radiator. When full, start the car and allow to run. You should notice bubbles coming out. When the thermostat opens, the coolant level will drop. You should continue to add coolant. This process usually takes about 30 minutes. Shaking the car also helps to evacuate air pockets as well. Good luck.

Sometimes radiators can develop blocks from coolant contamination(rust and such) and cause overheating as well. A radiator shop should be able to remove those blocks.

[juno]

Thank you Orestes and Nissanfanatic. I tried everything you suggested and it worked. I took the car for a 30min spin afterward and the car did not overheat. Wow, I have changed the radiator fluid five times in this car and never had that problem. Good lesson to learn for the future.

Thanks again,

-J

[nissanfanatic]

Just for an explanation, when you have air bubbles in the cooling system, it causes the thermostat to close. Some people expirience this problem at idle, others at cruising speed. I'm glad you got it fixed.

[mynismo]

i know exactly what your problem is



thermostats from autozone do not have air bleed holes in them (did you notice that when you compared it to the one you took out?)

throw it out, go to nissan and pick up a real nissan thermostat with a bleed hole. that is very likely the culprit.

also remember when installing it that the air bleed hole points straight up.

[Chuki_breath]

sounds as if he fixed, regardless a nissan thermo still might be better. But since it works now screw it.

[D-Bo]

Originally Posted by nissanfanatic

When filling the radiator, make sure you have the temp setting for climate control on the highest heat setting. Then commence in filling the radiator. When full, start the car and allow to run. You should notice bubbles coming out. When the thermostat opens, the coolant level will drop. You should continue to add coolant. This process usually takes about 30 minutes. Shaking the car also helps to evacuate air pockets as well. Good luck.

Sometimes radiators can develop blocks from coolant contamination(rust and such) and cause overheating as well. A radiator shop should be able to remove those blocks.

you can pinch the hose nearest the spout that you're putting the coolant in.. that pushes the air out too..