cherokee_99

Can machine shops fix cracks? The one I took it to could not detect a crack in the head. I'm just wondering if they missed it. I'll grab that pressure test kit in the next day or 2 and give it a try. Any place I can read instructions on how to use a kit like that?

Kalali

I have yet to hear anyone having success "fixing" a cracked XJ head.

coloradocherokee

Do you have s 99 cherokee?

cherokee_99

It's a 1999 Jeep cherokee sport, 4x4, 2 door, 4.0 6 cylinder

cherokee_99

So if it's a cracked head, I assume I need to either get one from a junkyard or buy a new one?

Don't try to have old one machined?

OleBlue

yea, once its cracked its no good. Buy a new one or get one from a jy.

partsguyct

Just be careful that one isn't cracked too

DFlintstone

Yea! ^, And don't get an 0331...unless you can find a "tupy" foundry mark inside under the cap. That's the " revised" 0331.

Like Old Blue mentioned. If it has 0331 on the drivers side, top edge it it almost centennially toast. I guess the 0630 is a pretty hardy head though. I doubt it's the bolt, sounds like a crack. Did the shop magnaflux it? If not that might be your next move. You could pressure test, but with milky oil...Idk. And no, no sealant for a head gasket, just that one bolt.

Do take some time, when you have the head off, with a really good light take a really good look at the cylinder walls. They DO crack, and sometimes you can see it. (you might do that first). Sorry btw. Years ago my feonsay melted a motor of mine, was only a mile home (after the light came on), but it was nearly straight up!

DFlintstone

And a compression check might make sense! (the more info the better)

cherokee_99

The shop did magnaflux it and found no cracks the first time so I'm not sure at this point what to do. So a pressure test won't help with one of the tools you can get from AutoZone?

cherokee_99

Pressure checked showed a leak..took off valve cover and saw some fluid seeping out of a crack in the top part of the head...thanks for the recommendation.

I'm looking at the Spartan cylinder head from Advance Auto...My local junk yard carries a head for $150 plus the cost to have it checked after I bought it buy a machine shop. So it's around $200 for a jy head or about $380 for a remanufactured head from Advance Auto.

Any reason why I shouldn't purchase the one from Advance? Will it hurt anything to put a head like that on a 13 year old engine block?

djb383

Sorry to change the subject, but can u verify whether or not your '99 XJ's head is original?, can it be identified with the 0331 marking?, what is the "build date" of your '99 XJ? (sticker on the drivers door pillar, Mo/Yr)

cherokee_99

It's actually the 0630 head...original. I've owned the vehicle since 1999. It's not the weak one that everyone keeps talking about but it is definitely cracked. Pressure test shows the liquid bubbling out at the head top portion near the valve cover.

My oil doesn't look milky though --- only in the valve cover is it milky..dipstick shows it clean looking.

cherokee_99

Would a small head leak cause the engine to overheat after ten minutes? That head crack is small and is only leaking a little fluid. I can see a head leak causing a miss but would it cause an overheat that fast?

OleBlue

Yea it could, the cooling system is pressurizing to where it needs to be at because of that crack, so the coolant isnt flowing like it should.