96 XJ Getting hot...

Reply Subscribe

Thread Tools

Search this Thread

Sep 18, 2014 | 01:19 AM

#16

phishsihp

Junior Member

Joined: Sep 2014

Posts: 44

Likes: 0

From: Atlanta > Cali

Year: 1993

Model: Cherokee

Engine: Straight 6

Mine may be running a bit hot too, subb'd

Sep 18, 2014 | 08:08 AM

#17

CMI86

Thread Starter

Junior Member

Joined: Sep 2014

Posts: 30

Likes: 0

Model: Cherokee

Quote:

Originally Posted by tjwalker

Deleting heater core should not be in play for your overheating. But with you in MN, are you willing to drive this XJ in the winter without heat? I'd SERIOUSLY reconsider this before the cold sets in. If you don't have good heat, this is a 3 season vehicle, period. I live in central MN and I remember more than a handful of days where the thermometer read -28 farenheit. Those days are not that far ahead.

I agree that a total overhaul of the cooling system is the best bet. Including a new heater core. Parts are cheap. You do the work. Put it up on the hoist at your work and have at it!

*Radiator
*Water pump
*Thermostat (195 degree, I recommend a MOPAR stat)
*Heater core (this is the repair that is the most involved; do your homework before digging in)
*Clutch fan
*50/50 mix of conventional (green) coolant. Either premixed or mixed by you with distilled water
*Radiator cap

Thanks for the input. No I fully intended on replacing the heater core when I bought the truck. I just want to get the cooling system nailed down before I put the HC in so I am not wasting all that brand new coolant.

Sep 18, 2014 | 08:10 AM

#18

CMI86

Thread Starter

Junior Member

Joined: Sep 2014

Posts: 30

Likes: 0

Model: Cherokee

Quote:

Originally Posted by Thax

Id seriously suspect poor radiator and or water pump performance. I wouldnt rule out a Head Gasket failure until both combustion leak and compression tests are performed.

That is what I am beginning to think. Combustion leak and compression tests were both performed and passed.

Sep 18, 2014 | 08:18 AM

#19

Fred/N0AZZ

CF Veteran

Joined: Jul 2013

Posts: 7,554

Likes: 17

From: Monett, MO.

Year: 1999

Model: Cherokee

Engine: 4.0

At the age of your XJ I would just replace them all and then you would have those bases covered, as they will need to be addressed soon anyway. You can never be wrong doing them at this stage.

Sep 18, 2014 | 08:23 AM

#20

CMI86

Thread Starter

Junior Member

Joined: Sep 2014

Posts: 30

Likes: 0

Model: Cherokee

Quote:

Originally Posted by tjwalker

Normally, overheating at highway speeds is related to the water pump or radiator.

Overheating at idle is more telltale of a clutch fan.

I looked in to the fan clutch this morning. I spun it stone cold and i got barely 1/4 turn out of it. I then ran it the 1/4 mile to work, parked it and let it idle up to operating temp (210 after thermostat opened) shut it off and spun the fan again and got a good 2 full revolutions out of it. Tell me if I've got this wrong but isn't the clutch supposed to spin freely when cold and not turn much if at all when hot ?

It is starting to make sense that my over all hot condition can be attributed to poor heat dissipation caused by either sub-par coolant flow or poor heat exchange through the radiator or likely both. I am just trying to rule out additional parts to keep costs down. Even at my cost parts are over $250 through NAPA.

Sep 18, 2014 | 11:39 AM

#21

Thax

Newbie

Joined: Nov 2012

Posts: 11

Likes: 0

From: NoVA

Year: 99

Model: Cherokee

Engine: 4.0L

OP if your in doubt of the condition of any of the cooling system parts , replace them. The XJ 4.0L is not forgiving of neglected cooling systems. The radiator is rather small for the size of the engine , and needs to be in top condition. I have used Spectra radiators and GMB water pumps in the past with great success. My 99 got a refresh last spring with a new Spectra rad, GMB pump , Imperial fan clutch , Stant thermostat , Gates hoses and BWD coolant temp sensor. My XJ runs great and via my scan gage II runs at a very stable 207 degrees , very few fluctuations even with ac on full max. I say if in doubt replace it and sleep well at night.

Sep 18, 2014 | 02:14 PM

#22

CMI86

Thread Starter

Junior Member

Joined: Sep 2014

Posts: 30

Likes: 0

Model: Cherokee

Quote:

Originally Posted by Thax

Well I noticed that the "indicated" temp my thermostat was opening was near 220 which isn't right so I am going to start by replacing that today and see where it goes from there. Maybe my gauge is just reading high.

Sep 18, 2014 | 06:12 PM

#23

CMI86

Thread Starter

Junior Member

Joined: Sep 2014

Posts: 30

Likes: 0

Model: Cherokee

So i started with the new mopar 195f thermostat and it is still not opening until like 220f on the gauge. I am almost starting to think my gauge is just off, I am sure it isn't an air bubble as i put a lot more coolant back in than came out doing the thermostat. I need an IR gun...