96jeeper

1996 jeep cherokee 4.0. Ive only had it 2 weeks. The first week it ran perfect, then one day i noticed the temp gauge creeping up and got it home. Hoses felt swollen like thermostat was stuck changed it first no difference. Here we are now. Ive read all over forums and seen same symptoms but i cant cure it and not sure what else to try.

Things ive checked and replaced

New water pump
New radiator and cap
New stant 195 thermostat (checked on stove too)
New antifreeze
New thermostat housing
New fan clutch
New temp sensor in head
new belt/idler
Cleaned overflow tank (bottom had brown sludge in it)

Flushed the head, block and heater core till they flowed clear
My heat works
My aux fan works

Ive tried burping air from radiator and temp sensor up on ramps

At idle it will run 230s and build pressure in radiator hoses till they are tight. But it seems too much pressure and not pulling or pushing any fluid into overflow, almost like low circulation or air. I haven't let it get hot enough to boil over. Running the heat or aux fan seem to keep it around 230 on the gauge but thats at idle any driving and it starts to creep up to 250+. Ive used a infared thermometer and shows 180 at housing at idle but driving makes it 220+ which seems fine but i can tell its hot it gets sluggish hoses really tight like air inside and it has steamed from the cap once when i got it to red. There is no exhaust smoke. There is no water/oil mixing and overall it runs good until it gets too hot and throws a p0171 since i noticed a manifold crack at the collector. Could this be all the cause?

Sorry i rambled but i feel like im chasing a ghost. Thanks for any help!

JSlaughter

I hadnt done as much diagnosing as you but I was running warm as well til I not only replaced my fan clutch but upgraded. Now I run about 210, maybe 220 on hot days here in utah (its been 95+) but it does pretty well.

https://www.napaonline.com/napa/en/p/TEM272310/

Its a stock clutch for a ZJ but bolts right up.

Here is another forum discussing the topic:

http://www.naxja.org/forum/showthread.php?t=1043528

I can say it is a bit louder and has a small loss of power but I can still pull my fishing boat just fine. Loss of power is better than no power cuz your sitting on the side of the road.
This may help to combat your overheating issue.

Anony

The serpentine belt is tight, no slippage?

Sounds as if the viscous fan isn't working efficiently. It can take several days for small air bubbles to work themselves out of a cooling system even though the cooling system has been burped.

There could be also be something wrong with the head that might not even be noticeable. Did you test the head for compression?
Test coolant making certain there's no oil and/or exhaust leaking into the cooling system.
Monitor for any coolant loss. Coolant loss can be internal (no ground spillage) or external (spillage is usually noticeable).
Monitor and test engine oil and exhaust, making certain there is no coolant leaking into the oil and/or exhaust. It's possible to have signs of coolant in the exhaust where the oil appears to be normal.

Running too lean (PO171) will cause the engine to run hotter and effect the efficiency of the cooling system.

96jeeper

The radiator was a replacement but i bought the vehicle used no prior history. I just replaced all the cooling components this week though with no changes. I dont think the fan clutch is my issue as it has all new parts and still goes to red.

Martlor13

Do you have a shroud? Do you have any loss of coolant?

96jeeper

Yes i have a shroud and no coolant loss. Thinking i may go ahead and replace the head gasket. It has 174k miles and has sat for a year or so. Also coolant overflow and radiator both had orange clay or stop leak when i started this project. Possible the head gasket passages are clogged or damaged? block too?

97grand4.0

My friend, you have already thrown a ton of parts and labor at this, time for some real diagnosing before you go any further.
Curious, have you had a scan tool on it, and what does the CTS show for temperature? I would not go a head gasket at this point, you're missing other symptoms like rough running, white smoke in exhaust..fouled plug etc.
When you shut the engine off, does the fan clutch stop spinning the fan almost immediately, or does it continue to spin?

96jeeper

scan tool has shows 205 at idle start driving and it goes to 230 and climbs. its like it doesnt move water properly. The hoses start to swell tight like back pressure to radiator. It was running rough at this point but only when driving. i have to have the heat or ac on for it not jump into the red tho. Plugs could be fouled i havent checked i have new ones to go in but wanted to fix this first. havent had any misfire related codes. only the code for running lean which seemed to only come when it started to run close to hot. Fan clutch operates properly.

At this point the only thing i haven't tried is the head gasket, it looks to have never been changed before. I can get the full felpro kit locally for $60 so its not a terrible hole in the pocket.

dave1123

One thing I have to mention. Is the water pump you put in the right one for your belt set-up? V-belts and serpentine belts drive the water pump in opposite directions. Maybe you got snuckered by a parts counterman. It's really hard to tell just looking at them unless you are familiar with pumps. The wrong pump will still pump, just not efficiently.

96jeeper

It was pumping normal until this happened. The previous owner had recently changed the water pump. I have pulled it off and inspected no wore down impeller or clogs/leaks. looks like every other new one ive seen. Dont think it would be the wrong pump when it was working a week ago.

97grand4.0

So you're going to replace a head gasket on an engine that is not known for head problems, that is not smoking out the tail pipe, and is not misfiring, without doing so much as a compression test. Got it. Let us know if that fixes it so we can make more suggestions.

How about a coolant pressure leak down and cap pressure tester, is the water pump the correct one, spinning the right way, serp belt routed correctly?

dave1123

delete

dave1123

Sorry, I thought you had replaced it. Have you flushed out the block? Drain plugs I mean.

96jeeper

Not necessarily its just an option. See above about water pump. belt is routed properly. i have not pulled any plugs on the block would this be any diff than flushing through thermostat housing or water pump? Also forgot i have ran it without thermostat too and get the same result.

dave1123

Any rust or trash will settle in the bottom of the block water jacket and if enough gets in there, it can block the flow thru it. I've pulled them out of Chevy V8s and had all manner of crap come out after probing the holes with a screwdriver.