How hot is it running ?Because the 4.0 in these jeeps run hotter then most engines.

 

When I first got it the oil was milky but I assumed it was from where it sat so long and got condensation in the oil. Since fresh oil and coolant I've put about 200 miles driving on it and a few hours of idling and both are clean and no added or lost fluid in either

 

After awhile of driving, up past 220-230 even on a 65 degree night.

 

Rad and pump where Id start.

 

Ok, cool that's what I'll do. Thanks

 

I'd do the test for exhaust in the coolant before spending the money on the rad and pump.

https://duckduckgo.com/?q=test+kit+e...ffnt&ia=videos

If that's clean, then yes, rad and pump, and before you put antifreeze in it, see my sig #4. There's time before freezing weather to leave it in there a month.

 

Wouldn't I be losing coolant though? Levels are the same for weeks.

 

Not necessarily. You could have exhaust gasses coming in, which will cause overheating, but not always have coolant going out.

The test isn't expensive, and the peace of mind is priceless.

 

I just assumed it was good since the coolant levels stay the same and no bubbles in the radiator. Ill do the test.

 

Do you see bubbles in overflow bottle when running ?

 

No sir. Im gonna do a good flush over the next few days and then fill with fresh coolant again. If it doesn't work then ill do the water pump.

 

I'd hold off on that expensive coolant until you know you have the problem solved. You can always drain some water and add coolant later. A few days or even weeks of running distilled water isn't going to hurt a thing.

 

If you save and reuse coolant then that is OK. But the comment about using h2o is a good one cause you will see what's inside the system a little more clearly. Good luck. HD water pump and new belt got me right.

 

When I do flushes, I always just go to Dollar General and buy their gallons of DISTILLED Water. I'll flush that crap through each system separately(Radiator ONLY & Heater CORE) after initially running water from garden hose through it. Then I'll FLUSH it through ENGINE by Pouring it through Thermostat housing with T-STAT out. That should give you a good FLUSH. You can USUALLY tell if your radiator is really gunked up by how quickly it flushes when your disconnect top hose and lower hose and pour a gallon of water through top hose. For this type of process you don't have to use DISTILLED water, When it RUNS CLEAN then I'll do the final pass with DISTILLED water as mentioned above.


Cooling Systems are not complex, Very few components to work with. If a new Radiator, Water Pump, T-Stat,Hoses, Fan Clutch, Fans don't fix the problem then you have a far more expensive issue at hand which is either Cylinder Head Crack that does not leak coolant into the Oil, but exhaust gasses going into the Water Channels. Like others have said, go get a COOLANT test kit. I think they're pretty cheap. In fact here is one:

 

Fwiw, my xj would do this when my aux fan quit coming on automatically.

how it should work: thermostat is normally 195
aux fan should auto kick on at something like ~227 I want to say from memory. and not turn off until below 215. or when A/c is turned on.

For me I just put mine on a switch/relay instead of troubleshooting it. Mine comes on with a/c but not automatically as it should when a/c is off. Tried a mopar coolant temp sensor and didn't fix it. So like i said I just hard wired it and haven't had an issue.

Mine would get hot around 220-235 after it was good and warm (20-30mins of run time) and then sitting in traffic. Knowing my cooling system was fresh....I Tried 2 stats and 2 fan clutches and the zj napa clutch. and the aux fan is what ended up fixing it for me.. I just flip the switch on anytime I'm not on the highway. I can sit in traffic with a/c on for an hour now and temp never climbs

It took me awhile to concede that the aux fan was mandatory for keeping my xj cool but It works for me and might work for you..