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Thoughts....coolant leak. Hopefully not the head gasket.

B

Brett M

NAXJA Forum User
Location
Salt Lake City Ut
Specs

1989 XJ 4.0, AW4 212K miles

So, the other night after finishing up some other work on the XJ, I was letting it run in the driveway. Low and behold, there's coolant leaking out from the front of the engine. Get out the flash light and looks like it's coming from above the freeze plug on the left front side of the engine block. I'm hoping that it's not the head gasket, but definately am not ruling that out.

Any guess on what else it could possibly be? So far, no oil in the coolant or coolant in the oil, though it's definately using up the overflow tank quickly! Just looking for any other places to check before hand.

EDIT: I doubt this matters, but the coolant system is converted to a 91+ open style system.
 
Muad'Dib said:
Are you sure it isnt coming from the freeze plug itself?
Click to expand...

It was hard to tell at night, but from what I could see from the Mag lite, it was dripping down into the freeze plug. I'm going to try and get a better look in the light, after work.

Freeze plug = much easier to repair.
 
jneary said:
front exhaust manifold stud goes through a water jacket. remove the stud and try to seal it with some teflon sealant and seal that head bolt too
Click to expand...

This is almost true.

The exhaust manifold stud doesnt actually go into a water jacket, but the head bolt does. The hole for the stud goes through to the hole for the head bolt if no bolts were there. So in all reality, it wouldnt leak out the exhaust manifold stud unless it was already leaking passed the head bolt.

The downside to this is that if you remove the head bolt, you have to remove them all (in sequence) and then re-torque them all (in sequence) once you have cleaned up \ applied some high temperature thread sealant to that head bolt. Also, if the head bolts have already been re-used or re-torqued, then they need to also be replaced (since they are TTY). In my opinion if you have to already get that far down into it, then it would be best just to remove the head... it really isnt that hard to do just time consuming without a hoist or by yourself.
 
Last edited:
jneary said:
you dont have to remove them all. thats the last one to tighten in the sequence. its safe to remove it and apply sealant to it and torque it to 100 foot pounds
Click to expand...

!! INCORRECT

Its # 11 of 14 in the sequence how could it be the last one???

Even IF it was the last one, you still need to do them all in stages or risk the chance of warping the head.
 
i guess it depends where you start. as long as you do it in a circular pattern you can end up at any of the end bolts and be fine. i choose to do that one last so i dont have to keep resetting my torque wrench. i may not be an IT guy, but i have fixed a jeep or 2 in my day
 
Muad'Dib said:
Are you sure it isnt coming from the freeze plug itself?
Click to expand...
Not to hijack but, just curious about your screen name......from Frank Herbert's Dune? :dunno: ---------Hans
 
Muad'Dib said:
Even IF it was the last one, you still need to do them all in stages or risk the chance of warping the head.
Click to expand...


and if you removed them all, you would mess up the head gasket. so whats the big deal to remove one bolt, reseal it and install it properly
 
Before you assume it's something larger, are you sure its not the water pump, thermostat housing, or a radiator hose that is leaking?

Leaks can originate somewher else and flow and make you believe they are coming from somewhere else. Just food for thought.
 
jneary said:
i guess it depends where you start. as long as you do it in a circular pattern you can end up at any of the end bolts and be fine. i choose to do that one last so i dont have to keep resetting my torque wrench. i may not be an IT guy, but i have fixed a jeep or 2 in my day
Click to expand...

Your right i didn't think of messing up the head gasket .. but then again, if it were me and i had all the bolts off, i would just go ahead and remove the head if i was concerned about the HG.

jneary said:
and if you removed them all, you would mess up the head gasket. so whats the big deal to remove one bolt, reseal it and install it properly
Click to expand...


Your also right about the sequence, but i want to make sure that anyone who comes across this thread doesn't get information that could end up royally screwing things up. To each their own i guess... some people have different ways of doing things... but i think we can all agree that to much crappy information floating around out there.
 
yeah but resealing that bolt only takes 5 minutes. its worth a try before you pull the head off. i have never seen a head gasket leak along the side. it usually blows between 2 cylinders, but you really have to get the engine hot. the 4.0 is a very durable motor.
 
Oatmeal said:
Not to hijack but, just curious about your screen name......from Frank Herbert's Dune? :dunno: ---------Hans
Click to expand...

Yep! May the spice flow!

jneary said:
yeah but resealing that bolt only takes 5 minutes. its worth a try before you pull the head off. i have never seen a head gasket leak along the side. it usually blows between 2 cylinders, but you really have to get the engine hot. the 4.0 is a very durable motor.
Click to expand...

x1000
 
Blaine B. said:
Before you assume it's something larger, are you sure its not the water pump, thermostat housing, or a radiator hose that is leaking?

Leaks can originate somewher else and flow and make you believe they are coming from somewhere else. Just food for thought.
Click to expand...

That's what I am hoping, as I really don't want to do a head gasket. I'm pretty sure it's not coming from the front stud as some have suggested (pretty sure I would have noticed that last night.) I don't belive any of the radiator hose's are leaking right now, but I will definately check those soon. Same with the thermostat...not sure on the pump, so I'll look into that one as well.

Thanks for all the idea's so far guys......oh, and no more pissing matches about stud's ;)
 
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