quick question

[DansGreyMj]

what is the normal running temp range of the 4.0 before it overheats

[Eagle]

210 on the gauge. It's actually a bit less in the engine but the sender is located at a hot spot -- rear corner of the head.

[87manche]

Mine stays at 200 deg highway, and heats to 235 when wheeling in 95* heat.

210 is the accepted normal op temp.

I pegged my guage at 260 one and boiled the coolant with no ill efect on the 4.0. My brother lost a radiator on the PA turnpike in construction and couldn't stop, he said the needle was at the screw past 260 and his 4.0 lives after he changed the new defective rad out in a parking lot.

4.0's are really tough, operating temps higher than 210 suggest something wrong with your cooling system.

[Pete M]

My 4.0L overheated on the dunes a few years ago and pegged the guage over as far as it goes. Still ran good enough to take me to Moab and back last year. :D

[Oizarod115]

my 89 MJ used to run at 250 everyday back when i beleived the PO about the sensor being off, its not. ive had to run it at 260 on the hwy before for hour and a half, my MJ runs great. it loves the heat lol. (knock on wood)

 

changing waterpump tomarrow.

[DirtyComanche]

I drove around in the middle of winter with mine with no coolant.

 

 

The gauge got pegged pretty bad. Every time I put the clutch in to shift it would stall, unless I stayed on the gas.

 

Otherwise it sits about 210. On the old mechanical fan.

 

The XJ stays at 190 with the AC on.