Jeep Grand Cherokee Forum banner
1 - 6 of 6 Posts

hrjaw

· Registered
Joined
·
88 Posts
Discussion starter · #1 ·
Good Morning,
I started having issues with my 99 wj with the 4.0, and would like to get some ideas from everyone. I replaced the water pump and thermostat 2 years ago, and it has been fine. Sitting in line for the car wash yesterday, and I noticed it edging over the 210 mark, which it never does. It actually made its way to the red zone. I went home and replaced the thermostat and the temp. Sensor switch on the thermostat housing and still it is overheating. It is doing this while it is idling, and cools off as you are driving. There was no loss of anti freeze, as it was at the full level, and I checked the oil, and no water in the oil, so I don’t think it is a head a gasket issue. This leads me to think that maybe the radiator is no good...but the funny thing is that even when it hit the red zone, and I had popped the hood to let it cool, it never overflowed. I don’t know if there is something else I should look at, or what suggestions you all have. I flush the system every two years, so I don’t think it is a dirty system, but you never know. Are there any other sensors, or a fan relay?
Thanks,
Roger
 
First off, not to insult your intelligence, but is the electric fan working?

the 4.0L motors are notorious for overheating issues. Make sure your fan shroud is in good condition. If you have a large crack in it or the shroud is missing, that can be the culprit.
Some XJ owners use a hood hinge shim/lift do allow heat to vent out of the back of the hood while the front remains latched. Still others buy and install vents in the hood right above the intake.
 
when you turn on your a/c, the electric fan will/should come on. Check your manual fan clutch and make sure that's it's locking up when the rig is hot.....alot of peole overlook the fan clutch-just because it's spinning doesn't mean that its fast enough
 
Discussion starter · #5 ·
A/C

Tried this when i got home last night. turned the jeep on, then turned the a/c on. my fan did not/ was not moving at all. i assume this means my relay is no good, which i can replace this weekend.
 
switch the electric fan relay with another one in the PDC just to check and see it that is the problem, it that doesn't help, check power and ground at the electric fan motor connector.
 
1 - 6 of 6 Posts