Coolant leak from exhaust manifold????
 

YEAH this is a new one for me.. then again I am pretty new to jeeps.

90 cherokee limited 4.0.

this started sometime between replacing the intake manifold gasket, and re placing everything else in the cooling system.





https://cimg6.ibsrv.net/gimg/www.che...b7f2ae98ff.jpg



this is the leak, I checked the freeze plug at the back of the head. a little oily but no coolant.

i did a block test.
https://cimg9.ibsrv.net/gimg/www.che...087f44303d.jpg

after 5 mins of pulling air from the rad
https://cimg2.ibsrv.net/gimg/www.che...1969998fa9.jpg

then sucking exhaust straight from the exhaust
https://cimg4.ibsrv.net/gimg/www.che...2e5510b55c.jpg


So my question is there a possibility one of the intake/exhaust mount bolts getting into the coolant passage??

you guys are stumped too huh?

The kid i got it from "rebuilt" the motor. could it be the head gasket is flipped?

i will be honest, this sucks. I've been playing 20 questions with these guys here, and getting a single problem solved 1 by 1. be patient. they will help. something aint right though. I've got a 90 and this is not one of my problems. they will help you though.

these beasts are some weird MOFO's.

I'm just glad someone replied. Saturday I'm going to pull the head and see whats going on. the kid i got the truck from was well.. my gramma would say bless his heart. if you get my meaning.

My guess is loose head bolt or possibly headgasket is flipped blocking the rear coolant passages.. but the truck would overhet like crazy if that was the case.. right? full up on coolant the temp gauge doesnt get past 200, usually stays around 180.

just trying to see if there is an easier fix than pulling the head.

You posted at 10PM your time, which is what, 3AM Eastern time?

Be patient. And please realize that a personal "emergency" on your part does not mean that everyone on here has the same sense of emergency in replying.

At this point, there are several possibilities as to why your Jeep is doing this. The first thing I would do is some independent research determining which bolts on the intake and exhaust manifolds penetrate the water jacket. Concentrate on those for the time being before jumping off the deep end and yanking the head.

Try simple solutions first.

firestorm has the right mind. just be patient as hard as it may be. there are plenty of smart guys on here that know their ****. they will direct you.

Thanks for the replies. I didn't take into account the time difference, I lose track of time in the summer as its almost midnight and still light out lol.

This is by no means an emergency, it leaks maybe a quart a day, and most of it burns off on the exhaust, no biggy.

I have done quite a bit of research and all I can find pertaining to a coolant leak in that area is the freeze plug on the back of the head, or older AMC 4.2's with the coolant passage in the manifold. neither of which help me. the only thing i found that was helpful was a thread where he just replaced the head gasket and got a coolant leak in that area.

So with my need to fix things and my inability to sleep when theres a problem I cant figure out I went out and pulled the valve cover and checked all the head bolts.

ALL of them were loose, not finger loose but they had maybe 50-70ftlbs. the rear two were the worst.

so I took my trusty,or maybe not so trusty beam torque wrench and put them to 110, except number 11 which got 100.

I dont know if this has fixed it yet and I will update tomorrow after work,

The joint between the head and block isn't far below the manifold. It's possible the coolant is leaking from there. There are coolant passages that lead right up to (but not through) the head gasket, so if there's any issue with the gasket, or the head or deck are warped, they can leak out that joint.

Whooda thunk it?

Great way to get after it.

I'm curious as to the results of your repair.....

Can't wait to see if it worked.

https://cimg4.ibsrv.net/gimg/www.che...6c6a608ec3.jpg

This was after a 45 minute drive home, 25 of which was sitting in grid lock.

I think it may just be fixed!! I will update if anything changes.

Great news! I don't think anyone would have thought to suggest checking to see if the head bolts were tight.lol. Good thing you couldn't sleep.

Yeah I'm really happy. working through issues one by one.

Heres before and after pics together to show the difference.


https://cimg0.ibsrv.net/gimg/www.che...d5adaf807f.jpg

https://cimg2.ibsrv.net/gimg/www.che...b9e16d4b4f.jpg

You have to be the luckiest guy alive!! Are 4.0s tough or what?

I do manage to get lucky once in a while.

I hear they are pretty tough, but time will tell. I'm used to old subarus which I have never been able to kill. and I tried a few times.

this was my last rig.
https://cimg4.ibsrv.net/gimg/www.che...252479a2b5.jpg