Hey all!
Currently driving a 97' XJ that has around 280k. Having a hard time trying to diagnose the overheating problem.
I know for a fact the water pump is no more than 4 years old and the radiator was replaced at the beginning of the year.
Sunday: It was driving just normal, a bit of a rough idle but nothing out of the normal. Didn't really pay attention to the temperature gauge, but I am sure it was running average temp. Drove it all day.
Monday: The idling got worse and randomly stopped when driving around. Parked it and didn't drive it much more after.
Wednesday: Tried to get to work today but this is where it all went down hill. drove about 20 mins and noticed temp gauge climbing up and the car started to shake. I pulled over and popped open the hood. White smoke was coming from below the water and steering pump?! No leaking? Waited about 30-45 min and it was bone dry so I topped it off with water.
When coming back home i first topped it off with water before leaving and drove about 3 min and it was a instant!! rise from the temp gauge. Running well above 210. Usually it takes more than 3 min. After about 10 min it would jump from about 210-230 back and forth until the idling and overheating got so bad i had to stop.

Any ideas? I hope it all makes sense.

Thanks in advance
-Jon

 

Do you happen to know what material the water pump impeller is made of? (Basically, is it known to be, or possibly may be, a PLASTIC impeller?)

I had some terrible overheating due to a plastic impeller water pump on my previous Jeep (2000 TJ) snapping off internally. There was no leak and no bearing noise, but obviously without moving coolant, the engine overheated in minutes of driving. The pump was no more than 4 years (and probably closer to 2 years) old when this occurred.

The smoke was probably leakage from the weep hole due to extreme over pressurization and then it burning up on the hot engine.

 

I'd start by reviewing all cooling system parts.

*First off, is the thermostat. Probably the most important component in regulating temp. I'd replace it with a Mopar 195 degree stat. Inexpensive thing to try.

*Was the radiator cap replaced when you replaced the radiator? If not, replace that too. Often ignored but important. Your radiator is likely not related to this.

*Water pumps can fail, being 4 years old doesn't guarantee function. Consider replacing it if you get stuck here.

I'd go one step at a time and not wander far from home until this is resolved. Unresolved overheating can lead to a blown head gasket or worse. Good luck and keep us updated!

 

Unfortunately I do not know what the impeller is made out of but i am going to check on it today.

Thank you!

 

Will do! Thanks a lot!! I will keep everyone updated.
Was honestly thinking it was a blown head gasket :/ hoping nothing wrong there.

Thank you!!

 

Not impossible but I'd rule out any basic cooling system failure first.

If you get stuck after ruling out cooling system, then perform a simple compression test on all cylinders. This is a good test for a blown head gasket. The compression spec for the 4.0 engine is 120-150 psi, with no more than a 30 psi variation between cylinders.

Good luck and keep us updated!

 

Quick update!

Well it is not looking good. Replaced water pump, thermostat, radiator cap, and bottom radiator hose. Now for some damn reason i can not keep the bottom radiator hose on the water pump?! It seems like there is major pressure that pops it off? In addition, white smoke blowing out of the tail pipe with some type of liquid spraying out of the exhaust with a really rough idle?! Its looking bad gents....sounding like a head gasket.

 

Hey Guys! Sorry its been a while.

Took the head gasket out for more experience and for fun. It looks to me that the head gasket is ok? No cracks or holes. The layers of the gasket are separated but I don't think that is considered blown? Im going to replace the gasket, replace some bolts, rockers, and rods. However, I still stuck on why the bottom radiator hose to the water pump keeps coming off? It seems like there is major pressure that pops it off? In addition, white smoke blowing out of the tail pipe with some type of liquid spraying out with a really rough idle?!
Any ideas?

Thanks in advance.

 

Any ideas? Before I put on the cylinder head back on.