Im at the end of my rope I have done everything I know of to fix the over heating issue. I have 95 xj sport 4.0l str8 6. I have replaced the water pump the thermostat heater core I have flushed the whole system and im still running hot, but only when im sitting still if im driving it runs at the right temp. PLEASE HELP! THANKS

 

Is your rad cap holding 15psi befor bleeding over to the overflow cannister? The pressure in the system effects the cooling ability. Have you topped up the system since the last work you performed as air can work its way out leaving room for more fluid additions to top up. It may come to the need to replace the rad. Can you see any of the core ends, is there any visible scale buildup that could be limiting flow?

 

I've had the coolant cap issue. It was only holding pressure to 9 PSI. However, mine only overheated when I was at an idle. It ran cooler as long as I was driving. Yours does the opposite so it might not be that.

Regardless you should check the cap, and if it isn't correct get one from NAPA. If you get it from anywhere else you should test it instead of assuming it works. Nothing's more frustrating then buying a defective part and assuming it works then finding out it doesn't (and then troubleshooting for days on end before finding out it was the cap again).

Always beware parts not from NAPA. Although I bought mine from Autozone and it worked that doesn't mean you'll be as lucky.

 

Replace the radiator, fan clutch and rad cap.

 

The one thing that you did not mention is if you checked or changed out the fan clutch. That would be the thing I would check before changing out anything else. It is very easy to check. Just give it a quick spin if it spins free it needs to be changed out. The fan clutch should have some resistance and should not spin free. But, it also shouldn't be to stiff. Let us know when you get it taken care of.
Good luck.

 

I agree with some of the others here.

The #1 cause of "temp creep" at IDLE ONLY (not when moving) is the fan clutch.

Often overlooked, inexpensive and easy to replace. I'd suggest you do so.

 

x2 fan clutch

 

I did for get about the clutch fan I have actually replaced it 3 times because the first two I got from autozone and they were both junk so I went to NAPA and got one. It seems to be working well. I haven't however checked the rad. cap I just figured it work bc I didn't see anything leaking from it.

 

youve replaced everything else why not

 

Especially for how cheap a rad cap is. It really couldn't hurt to get a new one. Although don't get it from autozone. Mine gave out after about 750 miles of use.

 

#1 fan clutch.. #2 check electric fan to make to sure it runs, should come on around 218 degrees or with A/C

 

What's working well? It's overheating, right? How old is the radiator?