Jeep Cherokee XJ Running Hot

[Nick1994]

Originally Posted By: mk378
Plain water can cause rapid corrosion. You may be doing more harm that good leaving it in there for days.
I posted above I bought 8 gallons of distilled water to use for flushing. I use the hose to flush through but I let that drain and top off with almost 2 gallons of distilled

 

[DoubleWasp]

Prestone is a wuss as a flush. Been there, done that. Leaves a lot of crud behind.

 

[CrAlt]

Originally Posted By: Nick1994
Originally Posted By: mk378
Plain water can cause rapid corrosion. You may be doing more harm that good leaving it in there for days.
I posted above I bought 8 gallons of distilled water to use for flushing. I use the hose to flush through but I let that drain and top off with almost 2 gallons of distilled


Rig the garden hose up to the top of the block (may have to remove Tstat, cant remember if there was a heater hose port on the top) and undo the lower hose. Just let it run until the water runs out clear. Block the bottom with your hand to let it fill up and then remove your hand to let it "flush" out.Do that a few times. Then do the same running through the radiator and heater core.

Also check to make sure that aux electric fan comes on as soon as you turn on the AC.

My XJ always ran 200-210 but never actually ran away and boiled over... but it doesn't get to 110 here

 

[Merkava_4]

Originally Posted By: mk378
If most of your driving is city and off road you might consider a solid fan drive, no clutch.


Absolutely - I never did trust those fan clutches. I'd either make the fan direct drive full time or I'd install a twin electric fan kit with two speeds. Seems like there should be a spacer block on the market to take the place of the fan clutch.

That's a real nice looking Jeep Nick. I dig that stock look with the stock wheels and the stock ride height.

 

[demarpaint]

Originally Posted By: DoubleWasp
Looks like a good application for the citric acid flush.


I agree, that would be a good starting point. Just be sure to do it with the thermostat removed.

 

[Nick1994]

Saturday I had a new Magnaflow catalytic converter welded on, the old one was definitely broken inside. You could hear the chunks when you tilted it around. That didn't solve the overheating, but it's quieter now.

I put in a new radiator today with new hoses. It still got close to 220 while idling today, 210-212 while driving on the freeway.

I'll drive it some more in traffic and see how it does.

 

[SwampSurvivor]

Try a 2.5L fan clutch on it - it will be loud as it's always engaged but it will keep the jeep cool at idle and when you are working it hard off road and such.

When mine had working AC, we were at rausch creek off roading in the bright sun and 95 degrees and it didn't crack 210 all day. Also pulled my camper there and back through the hills (some of which it could only pull at 4K in 1st gear) and didn't crack 220 ... and that was when it was running at 4K for a minute or two.

 

[Kruse]

Originally Posted By: Nick1994

I put in a new radiator today


Care to tell us what brand?

 

[Nick1994]

Originally Posted By: Miller88
Try a 2.5L fan clutch on it - it will be loud as it's always engaged but it will keep the jeep cool at idle and when you are working it hard off road and such.

When mine had working AC, we were at rausch creek off roading in the bright sun and 95 degrees and it didn't crack 210 all day. Also pulled my camper there and back through the hills (some of which it could only pull at 4K in 1st gear) and didn't crack 220 ... and that was when it was running at 4K for a minute or two.


The Napa fan clutch really does spool up and move a lot of air. I'll consider the 2.5 fan clutch though.

Originally Posted By: Kruse
Originally Posted By: Nick1994

I put in a new radiator today


Care to tell us what brand?
It's whatever they have at Parts Authority. My mechanic uses them all the time and has never had an issue. He has one in his Jeep and my brother has one in his Jeep, no issues at all, they run cool.

 

[DoubleWasp]

That hot on the highway with a new radiator?

We can rule out fan or fan clutch. Not in play on the highway.

I'd flush that engine out with the block drains removed, and then acid flush that thing. XJ radiators are small, but 210 on the highway? Something wrong there.

 

[Nick1994]

Haven't driven it since Monday. Did a compression test on a cold engine, spec is 120-150 psi with a maximum variation of 30 psi. Results below
Cylinder / PSI
6-125
5-145
4-150
3-150
2-150
1-145

Also used a combustion leak detector to test for a bad head gasket. Test came clean, fluid was still perfectly blue.

I'll drive it some more next week and see how it does.

 

[OVERKILL]

6 looks low from the above. Do you have a leakdown tester?

 

[Nick1994]

I've replaced the thermostat again with a Murray high-flow, no temperature change compared to OEM.

Replaced temperature sensor and verified with a scan gauge. No change

I replaced both oxygen sensors with OE Delphi. No change

I welded the crack in the exhaust manifold (was about 1 foot down, all Jeep 4.0s do this). No change

I replaced the fan clutch today with another from Napa (stock one). Old one was leaking oil.

After the fan clutch today it seems to not cross 212 at idle, which is a lot better! 205-210 on the highway. Towing my small 1,000 pound trailer up a hill today it got to 220.

I might get a heavier duty fan clutch and let it roar.

 

[another Todd]

Check your radiator for plugging.

 

[Nick1994]

Temps are back up even after the fan clutch replacement.

220 at idle and in traffic
210-212 on the freeway with no traffic

It runs a little cooler without a/c on.

Any other ideas?

I'll list a complete list of what I've done again:
Tried 2 new thermostats, OEM & Murray high-flow, same result
New fan clutch
Flushed cooling system 5-6 times with distilled water
Electric fan works good
New radiator and hoses
New water pump last year
Coolant is at 60% distilled water and 40% antifreeze
New catalytic converter
New temperature sensor (same temp with IR temp gun, on my external gauge not the cluster gauge, and on scan tool)
New O2 sensors & welded up exhaust manifold crack

 

[AVB]

Is the thermostat in backwards?

 

[Nick1994]

Originally Posted By: AVB
Is the thermostat in backwards?
Nope

Forgot to mention in the list:

New radiator cap
Did a compression test, came back fine
Did a cumbustion gas leak down test, tested fine.

 

[Warstud]

Originally Posted By: Nick1994


I'll list a complete list of what I've done again:
Tried 2 new thermostats, OEM & Murray high-flow, same result
New fan clutch
Flushed cooling system 5-6 times with distilled water
Electric fan works good
New radiator and hoses
New water pump last year
Coolant is at 60% distilled water and 40% antifreeze
New catalytic converter
New temperature sensor (same temp with IR temp gun, on my external gauge not the cluster gauge, and on scan tool)
New O2 sensors & welded up exhaust manifold crack


Keep throwing parts at it...eventually you'll find the problem.

 

[supton]

Maybe you just need to move. I hear upstate NY is getting cool.

Is the engine pinging? I'm wondering if this is a "it runs fine, so let's ignore it" sort of issue.

Still think the radiator is too small or otherwise not getting enough airflow over it.

 

[Nick1994]

Put in a larger fan clutch today, it really roars now with air flow, still same temp. Still glad I did it though in case I'm pulling a trailer in the hills.

I guess I'll just leave it be and drive it how it is.