ZJ overheating...

[Jpdst29]

just got my ZJ back from the shop for a broken valve spring...drove it the 2 miles home...and i noticed the temp gauge was at +210

before i took it to get fixed, it always read -210, more around 180

it was still climbing as i got home...i am going to take it out longer tonight and see if it redlines the temp gauge

do you think my thermostat needs replacing and if so, should i replace it with a 180 degree aftermarket one?

some other possiblities could be i need to clean my radiator, need a new radiator, or new water pump, or new fan clutch???

any help would be great...thanks

[Jpdst29]

just took the Jeep out for a decent 30 min ride to see how much it overheated...maxed out at 235 and then flucuated between 210 and 235 up and down every couple minutes...got out and heard three distinct ticks right after one another...didnt hear it again so i am not too worried...

does the temp gauge flucuating that much indicate i need a new thermostat...it flucuated like that before...but between 160-190...so now it is just at a different temperature range...very odd

[Bill]

I know this may sound ridiculous... Did you check to see the routing of you serpentine belt? I know if they ripped apart the motor and the belt is not tight you may have water pump issues. (I did at one time on a GM car I once had.)

You may need to do some flushing of the rad / new thermostat... couldn't hurt.

Did you check your fluid levels since you got it back from the shop? That may give you some insight as well.

If the ZJ is going to continue to provide a hurtin on your wallet you may want to consider trading it in. I know you have been having a lot of problems with it, I am not sure where it stands as far as reliability is concerned, or if it is you DD. If it is your DD and you depend on it to get you back and forth to work then you may be better off with a new ride.

Just my $.02

[Jpdst29]

thanks for the insight bill...i have always considered trading it in...just paid it off and i love the no car payment and lower insurance...plus...i would get pretty much diddly squat on a trade in...

i would probably be better off saving up a decent size down payment and getting a second vehicle

[OverkillZJ]

High mileage trade in ZJ's aren't worth didly squat.

But they could have the belt on wrong. It's entirely possible for the belt to be routed in such a way that the water pump is actually turning backwards...

Don't drive it when it's hitting 235 - period - if you actually want this thing to be repairable at all. Much above that and you're looking at blowing out seals and warping the heads.

[Jpdst29]

i checked the belt this morning...it is on correctly

i am thinking it might be the thermostat...my upper radiator hose isnt getting hot at all...

could this be the problem???

[OverkillZJ]

i checked the belt this morning...it is on correctly

i am thinking it might be the thermostat...my upper radiator hose isnt getting hot at all...

could this be the problem???

Possible, or low fluid, or water pump, or.. .or... or.....

[dp]

Don't put a 180 in if it calls for a 195...that's NOT the answer. If your hose coming out isn't getting warm, then I'd say the tstat is sticking closed and should just be replaced with the OE temp one.

Remember...if the problem is elsewhere, switching to a 100 degree tstat isn't going to help you if it's climbing to 235+ degrees -- the tstat controls the minimum engine temp...not the maximum. So if it isn't the problem, it will still climb to 235.

I'd flush it out really good, and replace it with the OE tstat and see what happens. Air in the system can do strange things as well and I'm not sure if there's a bleed valve on your particular vehicle or not.

Another thing to consider would be investing in a multimeter. Check the temp of the coolant at the cap (take the cap off before your engine warms up) -- it's not too uncommon for the temp sensor to go bad and report a false reading when everything could be working properly.

hope that helps.

[Jpdst29]

thanks for the help deapee!!!

[OverkillZJ]

Don't put a 180 in if it calls for a 195...that's NOT the answer.



ZJ's should have come with 180 tstats in the first place. do NOT replace it with the stock 195 sensor, it defaults to closed when it fails, and gives you a similar (or same) situation to what you have now. Use a Robert Shaw or (I can't remember the other name now).



Another thing to consider would be investing in a multimeter. Check the temp of the coolant at the cap (take the cap off before your engine warms up) -- it's not too uncommon for the temp sensor to go bad and report a false reading when everything could be working properly.


Removing the cap and using a multimeeter isnt' going to do jack, the system will not heat up as normal with the system de-pressurized.

Besides, if that upper hose isn't getting warm, there's most definately somthing wring (not the temp sensor.)

If you want to come over and argue with me about it tomorrow, we'll be fixing it in my garage.

[dp]

I don't want to argue with you about it. Like I said, don't put a 180 in if it came with a 195 OE. And...you are wrong, however -- the coolant will surely heat up as normal with the cap off.

Please explain to me how the coolant won't heat up if the cap is off...that's absurd. If that were the answer, people wouldn't run cool air intakes, they'd just run their cars with the caps off their radiators.

--

I do have an associate's degree in automotive technology -- take it for what it's worth...or don't take it at all, the choice is up to you...sort of like how you wanted to argue with me for 2 days before you realized your calipers were on upside down...I don't just open my mouth to hear myself talk...only to help, and only when I know I'm right.

[OverkillZJ]

I argued with you when my calipers were on upside down? Actually, I never argued with you at all, and considering we flipped them 5 minutes after I found that the pedal was mushy, it wasn't 2 days. We flipped them as soon as you suggested it. Though the picture in my FSM still shows them upside down, POS. Don't make something out of this that it isn't, I was wrong, and I've never denied that.

I mis-stated the cap being off, my bad. I was thinking pressurized system means cooler system. I forgot the system is pressurized since the coolant boils at a lower temperature pressurized, not runs cooler. I was wrong again, I’m human. It happens once in awhile, believe it or not.

As far as the tstat goes, I've been dealing with overheating ZJ's for 5 years before you had a Jeep. I'm not coming from a know a little bit about every vehicle and hold a degree in it standpoint, I'm coming from a "we all do it and it works standpoint." And I'll stand by it. Especially considering my ZJ used to overheat here in 80 degree weather, and I drove it through Kansas at 100 running the A/C without a problem now.

180 tstat is your friend. Staunt is a good one that can be had locally, and it fails open instead of closed, unlike the stock piece of crap.

It's a ZJ thing, and DaimlerChrystler doesn't understand.

[PK]

My guess: low fluid. If they tore your engine apart, I find it to be very coincidental that suddenly your thermostat is also suddenly stuck closed.

I do find a lot of correlation between engine apart, and failure of engine techs to refill the system with coolant. At least with my XJ with the external reservoir, filling the coolant required several hot/cold cycles to circulate the fluid around to get an accurate reading on how much fluid it had. They may not have taken the time.

Remove the top radiator hose and let the engine heat up. If at around 180-190 degrees or so, you see no fluid circulating back towards the engine, you're low on fluid. It doesn't matter what the thermostat is doing if no fluid is coming back through the top hose of the radiator.

Thank you, and good night.
Patrick

[LordAthens]

They already fixed it. It was the T-Stat

[OverkillZJ]

Low fluid was the first thing that crossed my mind, but the system was full. We replaced it with a Staunt 180, made a mess of my garage and went to the Houston playground to beat the crap out of it.

I'll tell ya.. that skinny white boy likes the skinny right pedal sometimes! It was fun to watch ;)

I took my dads WJ there for one last blast offroad before it gets traded in for the WK soon :?


You know what though? After the playground, Jerome came back to my garage and cleaned it up BETTER than he found it. Maybe the rest of you that wrench over here could learn from him? Hell, he even hauled away about 5 gallons of old oil I had here! :idea: :lol:

[Bill]

You know what though? After the playground, Jerome came back to my garage and cleaned it up BETTER than he found it. Maybe the rest of you that wrench over here could learn from him? Hell, he even hauled away about 5 gallons of old oil I had here! :idea: :lol:

Watch it now... you know I am a cleaner. :D

[dp]

glad you got it fixed.

I wasn't trying to point a finger at you, Matt...just trying to share my knowledge on the subject. I realize you have dealt with jeeps long before I have ever known that some tj's come with a dana 35 and some come with a dana 44 -- it was never my intent to argue that. I can guarantee you, however, that I've changed 100 times the number of tstats that you have changed and probably 500 times the number of brake pads as you etc... I was trying to say that (and I have no clue what temp tstat a ZJ comes with) masking an overheating problem with a properly functioning 195 degree tstat by putting in a 180 is only that -- masking the problem, and not finding the solution. I'm not saying I'm better than you or that I know more than you -- just the tone in your response came off as 'demeaning' and provoked my somewhat belittling reply.

Again, sorry if I offended you as I didn't mean to.

[OverkillZJ]

Keep chaningin' those brake pads, cause the only pads I want to change are on ZJ's :D

Actually I'll just keep fixing Jeromes ZJ... So he can paint what needs painted in my house :P

[dp]

:D