No power, over heating, and odd moan...

I feel like my jeep is falling apart on me.

I have an intermittent overheating issue, seems random when it wants to jump to the red line, and it'll move there from one tick above half in a few seconds and then it'll move back down just as fast. If I stop and open the hood when it's at Red line it's hot.
I have a new thermostat and a coolant flush. Ran the hose from both sides cleaning out the fins of the rad. Fresh oil change.
Sometimes it starts like a champion, but if it's had a couple over heating spells it'll hard start and kinda rough idle for a minute or so.
Cap, rotor, plugs and wires aren't very old, maybe 20,000km

And I have no power, I can't go any faster than about 75mph. If I mash it to the floor it just won't go faster. Rpm are about 3400. Acceleration at all speeds is pretty dismal.
Also terrible mileage, 10 mpg or so. I tried the seafoam in the fuel, but hasn't helped anything.
I have 31" tires.


And the odd moan, the sound is coming from the front, and it sounds a lot like Mt tires on pavement, but louder. I had just thought it was my tires, but when I turn left on the highway, anything more than a 20 degree turn, that moan and vibration go away for the turn. Turning right doesn't have any affect.
I just got an alignment. Both wheel bearings have been replaced with no affect on the moan. Nothing feels loose. I had the diff open putting a lunch box locker in and everything looked normal, no metal in the oil or anything.



Now normally I would just Park it and leave it, but I'm using it for work the next couple weeks and these issues are not helping anything. Jeep has 180,000 km on it.
Edit.
1999 4.0l auto. 4*4. 5.5" lift. Slip yoke eliminated. Long arms. Adjustable track bar, drop pitman arm. Bumpers. Winch on a disconnect plug. 31" Mt tires. Stock gearing.

I'd like to avoid just throwing money at it if possible.

Year, engine? Any modifications?

1999 4.0l auto. 4*4. 5.5" lift. Slip yoke eliminated. Long arms. Adjustable track bar, drop pitman arm. Bumpers. Winch on a disconnect plug. 31" Mt tires. Stock gearing.

Under what conditions does it go into the Red?

Did you do the Thermostat to try and fix this and no change before and after?

I'm inclined to think you have a timing problem or plugged cat and a head/head gasket problem.

Re: Re: No power, over heating, and odd moan...

md21722 said:

Under what conditions does it go into the Red?

Did you do the Thermostat to try and fix this and no change before and after?

I'm inclined to think you have a timing problem or plugged cat and a head/head gasket problem.

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I tried to figure out what makes it climb into the red, but heat on or off, ac on or off, idling or driving. It seems random.

I did the thermostat and flush to try and fix this problem. But it seems the same, although it only goes to the first red mark and not the pin. But it still acts like a thermostat, like it sticks and then opens.

How would my timing have gotten off and how do I fix it?

How do I diagnose the cat?

I don't think it's a head or gasket issue, but I'm not really sure how to check that past visual either.

If you turn left and the noise goes away, the most likely thing is that your left front unit bearing (wheel bearing) is shot. The bearing gets quieter because when you turn left, the weight of the car pitches onto the right side tires. When you turn right I would usually expect it to get louder but not necessarily. I'd look with a flashlight at the back of the bearing. If it's real grimy / original, replace it.

As for the over heating.
It's a 99, so the timing would only be off if the chain had jumped. At 180,000 KM, I doubt it.
You might have a problem in the gauge circuit. Quick swings up to the red & back down aren't typical of a system with a couple gallons of water & a radiator in it. If it really is happening as fast as I think you're telling us, I'd be more suspicious of a bad ground connection somewhere or maybe of your coolant temperature sender. On your '99, there is only one of them : on your thermostat housing.

If you buy a IR temperature gun, you will be able to verify your actual temperatures in the driveway. It's a great tool and you will continue to have occasion to use it as long as you work on cars. This way, you can verify "gauge" or "engine" and start trouble shooting that way.

Do some google searching for how to clean the grounds on your XJ (I'm lazy and should be getting dressed for work) and change your LF wheel bearing. If your engine is really overheating, stop driving it until you have fixed the problem. You'll be replacing more than a water pump if you don't.
The lack of power, if it's the same root problem as the temps, is troubling. Do you have a check engine light on?

Have you installed a new radiator recently or is it original?

I have replaced both wheel bearings already. Caused no change in the noise. And when I said left I meant turn right and the noise stops. The pass bearing is 1000km old, drivers 8000km.

The temp will climb in 2 seconds, stay at the first red tick for a seemingly random amount of time, few seconds to a half hour, and then will go back to that first tick after half 2 seconds.
I'll pick up an ir gun what part should I be testing?

No check engine light. When the temp hits the red tick the check gauges light comes on.

I'll clean the grounds too.

It's the original radiator.

I never had any over heating problems with my original radiator until a tank finally cracked. Replaced it with an "original equipment" rad from O'Reilly's. It worked fine in cooler weather and at low speeds around town in summer time, but with hot summer temps and freeway speeds I would get the same exact symptoms you describe. With a little research on here and elsewhere I decided to replace with a Mopar Heavy Duty radiator. It was for '99 thru '01 model years but dropped right into my '97 with no fitment issues at all. Problem solved.

It could be that your original radiator is just done and can't flow enough anymore to keep the system cool. Good luck.

I think his cooling system is totally fine. Theres no way his engine could be getting that hot and cool off that quick. I would check for faulty wiring, or sending unit, or maybe even the guage itself

It's possible, just passing along some first hand experience with an issue that seems to match his issue which is: On hot days at freeway speed or maybe wheeling (really any extra load on the engine) the temp gauge would suddenly redline but not quite overheat, warning chime, check engine light, needle would stick there for a bit and once the load was reduced the temp gauge needle would literally drop back to near normal temp in a couple seconds. After chasing this for quite some time and piecing together bits of info from numerous threads, I swapped out the O'Reilly $100 radiator that was pretty new and swapped in the Mopar HD Rad. All my temp issues cleared up instantly. Sounds to me like his old original radiator may be done and no longer flowing adequately to keep the temps in range. Take it for what it's worth.

Edit: It's almost like once the engine reaches a certain high temp, its tripping a warning in the temp system/gauge, before it overheats. But I've never heard if this something thats actually built into the cherokees or not... maybe later models.

It sounds plausible that the a Jeep might jump suddenly on the dash if its already hotter than normal, but I don't know for sure. I got the idea that it went from normal to overheat randomly. I have had temperature gauge drop and raise randomly and I sprayed contact cleaner to fix. Another time I had removed the fail safe thermostat because it would do that whenever I stepped on the skinny pedal.

LawlessXJ said:

I never had any over heating problems with my original radiator until a tank finally cracked. Replaced it with an "original equipment" rad from O'Reilly's. It worked fine in cooler weather and at low speeds around town in summer time, but with hot summer temps and freeway speeds I would get the same exact symptoms you describe. With a little research on here and elsewhere I decided to replace with a Mopar Heavy Duty radiator. It was for '99 thru '01 model years but dropped right into my '97 with no fitment issues at all. Problem solved.

It could be that your original radiator is just done and can't flow enough anymore to keep the system cool. Good luck.

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I have thought about that, but just wish I didn't have to blindly throw cash at it to find out if it would help.
It's somewhat cool here right now, and I can't consistently get it to happen under any conditions.

josh9mile said:

I think his cooling system is totally fine. Theres no way his engine could be getting that hot and cool off that quick. I would check for faulty wiring, or sending unit, or maybe even the guage itself

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I'm thinking wiring, I'll have to check and make sure everything is good and clean.


I ordered and IR temp gun, should be here tomorrow, does it matter where I test on the engine?




I also ordered a new drivers site wheel bearing, for the 50 bucks it's worth doing, since I had a shop do it the first time, and I have trust issues. It should be pretty obvious if it is original right?

For the cat, if it is done, how bad would going straight pipe in its place sound? I don't have any emissions or anything to pass here, and hardly ever drive it. But if it's going to be louder I'll replace it with something proper.

It would be a bit louder with a straight pipe but as long as you have the muffler, probably won't do any hearing damage.
The shop probably did replace the bearings. They might have used cheap ones, or they might have gotten one that was mid range or even Timken or the like, and was bad / defective right out of the box. It happens. It also happens that sometimes I'm wrong - but the symptoms you describe are most often a wheel bearing.
I would test right at the thermostat housing. If the gun says the Tstat housing is 195 degrees and says a pot of boiling water is 212 but the gauge says the Jeep is 250 (or anything but 195) then the gauge is wrong.
Boiling water is a good calibration tool - you can even compensate for barometric pressure vs boiling point if you want - but it's pretty darn steady.

I lost all power after my cat got clogged. I couldn't even hold 65mph on flat ground. At the same time the jeep would overheat. Test it by just unbolting the cat. its going to be loud as a mofo strait pipe dumping under the cabin but if you get your power back and no overheating then that could be it. You can easily look inside the cat with a flashlight and see if looks all damed up

yossarian19 said:

It would be a bit louder with a straight pipe but as long as you have the muffler, probably won't do any hearing damage.
The shop probably did replace the bearings. They might have used cheap ones, or they might have gotten one that was mid range or even Timken or the like, and was bad / defective right out of the box. It happens. It also happens that sometimes I'm wrong - but the symptoms you describe are most often a wheel bearing.
I would test right at the thermostat housing. If the gun says the Tstat housing is 195 degrees and says a pot of boiling water is 212 but the gauge says the Jeep is 250 (or anything but 195) then the gauge is wrong.
Boiling water is a good calibration tool - you can even compensate for barometric pressure vs boiling point if you want - but it's pretty darn steady.

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I do agree that the symptoms are wheel bearing for sure. And it could have been bad from the start, my bill says oem wheel bearing. I found a new one that someone never got to installing before they sold their jeep, picking it up for a case of corona. So shouldn't take much more than an hour to replace and will no for sure if that's it.

I'll find out the IR readings too.

themauler said:

I lost all power after my cat got clogged. I couldn't even hold 65mph on flat ground. At the same time the jeep would overheat. Test it by just unbolting the cat. its going to be loud as a mofo strait pipe dumping under the cabin but if you get your power back and no overheating then that could be it. You can easily look inside the cat with a flashlight and see if looks all damed up

Click to expand...

I'll unbolt it (do they unbolt?) and see how that does here today.
If I straight pipe the cat I'll need to bypass the upstream O2 right?

OH. Another trick. Doesn't always work, but, take the car for a drive on the highway. Get that moan goin' for 10-15 minutes. Shoot the IR gun on both wheel bearings. If one is decidedly hotter than the other, you can expect it's bad.