Blown Head Gasket!

[Mudderoy]

As I suspected for some time now I have a blown head gasket on the 1998. I ordered the exhaust leak test kit from Amazon the other day and didn't get around testing the Jeeps until today.

I tested the 1998 after driving it an hour home. It turned yellow pretty fast. I have the two chamber kit that is supposed to help resolve the false positives.

I also tested the 1999 but it had not been driven today. I took the cap off the radiator and ran it about 15 minutes then tested it, only once because I wasn't too sure that I was testing it correctly, it being cold and all.

It did NOT turn yellow. It stayed blue. I'll test it again after it's been driven and the system is hot.

[Mudderoy]

So I'm considering my options.

I can pull the head off check to see if it is warped, and if so, take it to a machine shop and have the head tested for cracks and shaved so it will be flat again.

The Jeep will be done for several days and there is a possibility that the head will have to be replaced. I guess there's even a change that the block would have a problem, but I understand that would be unlikely.

Or I can buy a rebuilt head, new valves etc... and pull the current head off and put the new head on. Then I could take that head to the machine shop and all the work done to it. I'd have a spare for two Jeeps!

Or with 170k miles on my 1998 4.0L I could purchase a long block. I would keep my current engine and rebuild it myself. I could then put it in the 1999 XJ (when I felt like it). Most likely I would just sit on it until I thought the 99 4.0L was having an issue then do the rebuild.

Does anyone have a suggestion as to a good place to deal with for rebuilt heads and short or long blocks?

[4.3LXJ]

Tony

I am a little leery of production rebuilds. There are a lot if times they cut corners or do something they shouldn't so they don't have to throw away a core. But that is just me.

[msmoorenburg]

ok here's my 2cents search for the good head (the desired casting numbers) at the jyard and have it reworked. I've priced the machine work local and its about 100+ parts

[bigjim350]

I am a firm beliver that if you test 10 xj's, 9 will show positive for a blown head gasket. Also I agree with Matt. Now if you saw ridges on the cylender walls when you have the head, then I would think about a rebuild

[Mudderoy]

Originally Posted by msmoorenburg

ok here's my 2cents search for the good head (the desired casting numbers) at the jyard and have it reworked. I've priced the machine work local and its about 100+ parts

Oh I like that, just won't know if it's cracked until the the machine shop gets it.

It would need a value job though wouldn't it?

[msmoorenburg]

Originally Posted by Mudderoy

Oh I like that, just won't know if it's cracked until the the machine shop gets it.

true but they do offer a 30 warranty

[XJ4IV]

this is interesting... I always thought a blown head gasket will give tell tale signs like smoking like crazy and TOTAL lack of power and obviously seizing ... Id put 100 bucks that mine is blown as well LOL so I guess the 4.6 stroker is up on the chopping block this winter YAY!!!

[4.3LXJ]

Blown head gaskets can have a number of symptoms, depending on where it it is blown. I have had them put out a cloud of steam with a miss. Or hitting on all cylinders and literally pouring out the side. Ten miles to a gallon of water. Or just a tell tale miss that wouldn't let me pass smog, like the last time it happened. They can only let loose in the exhaust and never miss, only get the pressure in the water jacket. It can be highly variable.

[Mudderoy]

Well to be accurate I should say I have evidence of exhaust gasses in my coolant system. How it got there I cannot say. The most likely cause is a blown head gasket, a crack in the head or block, or a warp in the head or block. I think the block being warped is nearly impossible.

[bigjim350]

Yeah I have never seen a warped block. Seen plenty of cacked ones though. Hell I cracked a 5.0 in half one time do to a nitrous hicup. But I doubt you have a cracked block

[4.3LXJ]

My son the destroyer can go you one better, he broke the back off his 351 doing burn outs.

Gaskets let go before heads warp.

[bluedragon436]

I am planning on picking up another long block, then rebuilding my current 4.0 into a budget stroker and then swapping the stroker back into the 98.. then maybe if I really want too I'll rebuild the other long block into a budget stroker for another project or for a spare... heck.. take your head and have it checked at the machine shop, and have it ported and polished while it's there..

[msmoorenburg]

Originally Posted by bigjim350

Yeah I have never seen a warped block. Seen plenty of cacked ones though. Hell I cracked a 5.0 in half one time do to a nitrous hicup. But I doubt you have a cracked block

pssst jim it's time to grow up and stop wanting to be bottle fed

[default83]

just pull it, check for cracks, have it rebuilt at a local shop, if you need a number i have some guys that my dad uses all the time, good guys, and throw it back on.

you can check the cylinders/block, but i seriously doubt there is going to be any problems there, to replace the whole engine would be alot of work just for a head gasket.