b4d93r

Hi everyone,

I need some advice, A couple of weeks ago when I made a small trip (about 60 miles) my jeep started overheating big time. The only way I knew this was the obvious signs of steam as my temp gauge isn't working. Anyway I thought it might be the thermostat so I changed that out today (haven't drove it since the issue started just in case.) Started it up and ran it for a while with the AC running just to make sure. I didn't see any leaks but after I shut it off I heard the boiling sound of coolant (no steam).

I was wondering if anyone has experienced this before and what it sounds like to you. I have a feeling it's the water pump but I'm not sure. Our local parts shops are all out of the Chiltons manuals so I can't refer to it to help diagnose the issue. If it is the water pump, whats the difficulty level of replacing it? Also does the 4.0L I6 use a timing belt or chain? I'm also taking into consideration if it's the WP and there is a TB I might as well replace that too. Going off the assumption it's like most cars now days where the timing belt should be replaced as long as I'm in there. (Preventative maintanace.)

Thoughts?

syncview

well, check your serpentine belt to make sure that if it isn't slipping or worn out.. The 4.0 inline sixes have a timing chain I believe, since I'm not at good at these things I would let the experts answer.

b4d93r

Excellent suggestion! I just did that cause my fiance' mentioned to check to see if I have all my belts. Was a little surprised to find only one. (At least all i could see was one.) So if I am only supposed to have one then it looked good and felt tight.

benennis

i have the same problem but for some reasion i cant figure it out....

98 JeepJeep

the 4.0 uses a timing chain... The water pump is mounted on the block directly... the timing chain cover is seperate. Replacing the chain is up to you.....wouldnt hurt. It sounds like you have little to no flow. Run the car for a while feel the upper radiator hose...Is it hott? you might want to loosen a hose on the top of the motor with it running to see if you have any flow...otherwise go ahead and replace the W/P and buy a new temp sender while you are there....and once the new Pump is installed get some RAD flush chemical and flush it out several times with water before you fill it up with fresh coolant. if it still overheats you have a blockage some where...id be looking into the radiator next...this can be checked with a infa red gun.......

syncview

yes you are only supposed to have one long one, if they are two, its broken

Did you check if the belt has enough 'rubber' left to hold and move the pulleys?

1989cherokee

Mine did this a few years ago and it was the cap on the reservoir. It did not seal very well so the pressure would pop it off a little and coolant would boil out. Check the cap.

Bigclubs

Sounds like the water pump is done. I would not drive it much until you replace it and make sure there is no more over heating.

My horror story- I had an 88 cherokee and was 200 miles from home stuck in traffic with road construction going on. I did not notice when my gauge pegged in the red until I had steam coming from under the hood. The coolant was soo hot that it burned a hole in the overflow bottle. I let the vehicle cool off some, added water and tried to make it to the next town @3 miles and "Thats all she wrote" Pegged in the red again, steam under the hood, stalled and would not start. Cooked the engine. Sounded like clanking metal inside when trying to start the jeep hours later. Cost me an engine.

Changing the water pump in not that difficult and should take 1 hour or less depending on your tech level. The most difficult step is trying to loosen up the surpentine belt depending on the year of your vehicle and how much corrosion is on the adjustment bolt. To help in loosening the required bolts it's best to unplug the electric fan (if equiped) and remove it and the radiator shroud. This makes it easirer to get to the water pump and power steering bolts. This will also make it easier to replace the surpentine belt later.

Skreed

The 89 is a closed system this tends to happen a lot. If coolant is coming out of the overflow tank it's prob the tank and cap it self. These tend to loose there ability to hold pressure over time.

Also what other kind of cooling system maintenance has been done? The closed system requires a lot of attention. If none has been done lately it might be time to start replacing stuff. Water pump is not hard to replace and while your at it you can replace the hoses and do a flush and fill.

If the water pump has gone bad you will most likely see dripping coolant coming from the bottom of the water pump from the weep hole. The coolant will usually gather on the lower rad. hose and drip from there, esp after you shut the truck off.

BTW make sure your not low on coolant.

Firestorm500

Might be a blown head gasket.

Mechanic can check for combustion gases in the collant.

b4d93r

UPDATE 6-14-09:
Well went and tried a couple of things today. Discovered that the coupler on the small hose coming from the thermostat nozzle had a break in it so I fixed that and let it run for a while. It ran for about 15 minutes then heard the rubber piece holding the reservoir creak and noticed the reservoir had grown a little in size and was starting to boil again. So I shut it off and now I'll need to look at other possibilities. At least I can rule out the Thermostat since I replaced it and fixed the little coupler. I didn't see any fluid under the Jeep or at least any that had color it in. It's been raining like a monsoon here over the past couple of weeks and it's all wet under the Jeep.

Just went and checked it, all the coolant I added is gone from the reservoir and the big hose coming from the radiator to the big opening on the thermostat nozzle is cold. The little hose is still pretty hot.

Firestorm500

Are you geting white smoke from the exhaust?

b4d93r

No thank god.

fantic238

hi, if your ckee is from the 80s and has more than 150k miles it is probably the radiator that is blocked with dirt. Take it off and if it is all metal like mine, unweld the tin with a torch (careful at the trans. oil junctions!) and use a wiper blade metal to extrude the dirt from the holes while u r letting water flow through it. U will see alot of brown/green dirt coming out. If u r not so good at welding, take it to the radiatorist. it will work fine after.

98 JeepJeep

this is not always the end all be all for head gaskets leaking...