Cherokees always leak on the batt side of the radiator, fins start to corrode and fall apart, will look kind of greenish. Just a observation. But it is ALWAYS the case when a cherokee comes in to work. ALWAYS on the battery side first.

 

Had the same problem with overheating within 15 minutes of driving and asked my friend at the jeep dealership. He informed me what to check (1) take a hose and spray the radiator from inside the engine compartment out towards the front. Many times dirt collects in the fins and needs to be hosed out. (2) with the engine runnning increase the speed at the throdle body and watch the fan clutch. The blades should increase in speed.
I did both and found when I increased the speed the fan blades did not increase as fast as the clutch and surpentine belt were spinning.
Changed the clutch fan assembly with a heavy duty unit which only cost $3.00 more than the standard replacement unit.
This corrected my overheating problem. Eventually I also had to replace the radiator
1-1/2 years later. I replaced the radiator and added a medium duty rated transmission cooler and now when I tow my 3000lb tent camper my temperature guage dosen't even reach 180 even in 90 degree weather and on hills.

 

What t-stat u runnin'?????

 

I am running a 180 I believe. Its new. Prob should've got the 195 though. But they didn't have it.

 

And it wasn't on the batt side..

 

What t-stat u runnin'????

 

Would my rad cap cause me to run hot within 15mins?

 

Yes and no.....rad cap does nothing with regard to directly dissipating heat. The rad cap raises the boiling point of the coolant and is a 2 way valve to allow some coolant to escape to the recovery bottle as the motor heats up and allows coolant to return to the rad from the bottle as the motor cools. It's possible the rad cap is not allowing coolant to return thus causing a low coolant level in the rad which could cause an overheat.

Check the coolant level in the bottle and the rad ENGINE COLD.

 

Well my rad in 40mins lost 1psi and my rad cap didn't hold ANY psi!!

 

My new rad cap, doesn't hold any pressure either.. they both do the exact thingin the pressure tester.

 

Take it back. Is a better quality brand available?

 

I used a better tester and the newer one does work better..

 

Can my radiator as it gets hotter expand the cracks making it to lose pressure and coolant??

Also can I put the pressure tester on it while its running?

 

Yes and yes.

 

Ok well I just took her on a 30-45min drive in the neighbor hood. she didn't lose any fluid,or over heat, she did get to the mark after 210 but stayed they're.

when I opened the hood the coolant going into the reservoir wasn't boiling like usual either.

So I think the new radiator cap fixed it? Could be wrong?