99 xj overheating

[99XXXJ]

I have had severe over heating and I just changed my oil and coolant. I changed the thermostat to start but still the same prob. I ran my jeep for 10 minutes and the top radiator hose was not hot at all, as well as where the fuel rail mounts to the engine, those were melting. Radiator, water pump? Need help big time!

[fredjacksonsan]

Try running it with the thermostat removed. You should see circulation in the radiator.


Did the problem start suddenly when you changed the coolant?

If so, you could have an air bubble in the system...try parking the Jeep with the front end about a foot higher than the rear, and have the radiator cap open.


Do you have any oil in the coolant, or coolant in the oil?

If so, you could have a cracked block. See posts in this section on the 0331 head that was used 99 and after for a couple years.

How long is it taking to overheat after you start it?

[DIVERHERB]

Two things come to mind. Are the electirc fans operating and when you replace the thermostate did you position the bleed in the thermostate at the top when you installed it.

[rhandwor]

After you have done the previous checks mentioned look at the top of the fins if plugged I would price a new radiator. Pep Boys used to have the best price if not a repair shop.
Collapsed hoses and the belt installed wrong on the water pump can cause problems.

[DIVERHERB]

As mentioned in the last post the rad could be at fault, but that is a cross flow rad and almost impossible to visually see the cores. Calapsed hoses will usually show up off idle under hight rpms. I have seen the belt put on wrong, reversing the flow of the pump though.