I think my head gasket is shot

[Markos]

I've got coolant spraying like a squirt gun, right where the cylinder head butts up against the firewall. The coolant is squirting right at the firewall, then dripping down by the tranny pan. I'm guessing that it could only be the head gasket.

Assuming that it is the head gasket, is it possible that I warped the head? This seems much less likely with a cast iron head, but I want to know what I'm in for. Where exactly is the coolant temp sensor located? My engine temps are hovering right in the 210 mark, same as usual. My fear is that the head is starved for coolant while the sensor goes about its business. Hopefully that isn't the case.

Any thoughts?

 

[Markos]

I forgot to mention that my exhaust hasn't appeared discolored. Also, my XJ is a '99 and I don't think that I have the 0331 head that is prone to cracking. It's probably been about 6 months since I changed the oil (don't drive the jeep much), so I can't comment on that either.

 

[redneckboarder]

well thats a pretty serious problem id drain the oil and check if for coolant before you hydrolock the engine

 

[TripleDuck]

I'm thinking you have a bad freeze plug.

 

[winterbeater]

X2 on the freeze plug. Common for them to rust out. Far as I know though, you will end up pulling the head and putting on a new head gasket anyway to get to the freeze plug. Still, it's better than the head gasket going on it's own.

 

[menos]

X3 on the freeze plug. I had one that had similar symptoms. If it is that freeze plug you'll be doing the head gasket anyway as you have to pull the head to get to it. While you've got the head off go ahead and have it checked out. If it doesn't need any work it shouldn't set you back much coin at all. Even if it does need work it's not very expensive to get the head decked.

 

[Markos]

I don't think it's a freeze plug. They are too far away. Also, I can only see the coolant leaking from the passenger side. Once again, I can actually see fluid squirting (intermittent like a squirt gun) onto the firewall from the far end of the cylinder head. I can't see the source, but I don't think it could have made its way all the way from the rear-most freeze plug.

 

[winterbeater]

Are you looking at the freeze plugs in the block? We're talking about the one in the back of the head.

 

[wim hoppenbrouwers]

Hallo. There is one freeze plug in the back ,you can't see on the picture.

wim

 

[Markos]

Are you looking at the freeze plugs in the block? We're talking about the one in the back of the head.

There is a freeze plug in the back of the head? One in the back of the block also? Tell me more!

How the hell to you replace them? It's tight back there. Tonight I'm going to use a mirror to get a better look.

 

[Markos]

Doing more reasearch. Good info about the head freeze plug in this thread:
http://www.naxja.org/forum/showthread.php?t=35447

 

[menos]

There are two freeze plugs on the back side of the motor. One in the head that requires you to remove the head to replace. There is also one at the back of the block that requires dropping the transmission and removing the flexplate to get to. I don't know of any way to replace those two without doing what I described.

 

[Markos]

There are two freeze plugs on the back side of the motor. One in the head that requires you to remove the head to replace. There is also one at the back of the block that requires dropping the transmission and removing the flexplate to get to. I don't know of any way to replace those two without doing what I described.

Thanks menos, you hit the nail on the head. I'm fairly confident that it is the cylinder head plug and not the rear block. The leak is very high up. That sucks that the head still requires removal. It might as well be the head gasket. I suppose I should change all the gaskets and freeze plugs while I have the head off. What a pain...

I found another thread that illustrates my issue exactly

http://www.naxja.org/forum/showthread.php?t=66322

 

[joe_peters]

You don't have to pull the head.

Pull the radiator, unbolt the motor and trans mounts with the engine trans on a couple of floor jacks, disconnect the fuel line(s) and any necessary connections and then move the engine/trans assembly forward enough to let you get in there.

 

[Markos]

You don't have to pull the head.

Pull the radiator, unbolt the motor and trans mounts with the engine trans on a couple of floor jacks, disconnect the fuel line(s) and any necessary connections and then move the engine/trans assembly forward enough to let you get in there.

I was wondering about this. I have a new transmission mount and M.O.R.E motor mount waiting to be installed. I'd gladly purchase a few HD floor jacks if it means that I don't have to pull the head. Have you done this yourself? Anyone replace the rear freeze plug this way? I'm also concerned about the other freeze plugs, but I need to get my Jeep up an running ASAP. I'm in the middle of a move.

 

[joe_peters]

Never on a 4.0, maybe a dozen times on other engines.

You can get to the other freeze plugs with relative ease, and they make tools for driving them in at weird angles.

We used to replace the camshafts in Volvos with the Peugeot/Fiat/Volvo POS V6 (same engine in a Delorean). Used to use a hole saw on the firewall after removing the dash, then close them up with a couple of body plugs. Of course those are wet sleeve engines and a royal pain in the A** once you pulled the heads.

There is almost always more than one way to skin a cat.

 

[Markos]

Never on a 4.0, maybe a dozen times on other engines.

You can get to the other freeze plugs with relative ease, and they make tools for driving them in at weird angles.

We used to replace the camshafts in Volvos with the Peugeot/Fiat/Volvo POS V6 (same engine in a Delorean). Used to use a hole saw on the firewall after removing the dash, then close them up with a couple of body plugs. Of course those are wet sleeve engines and a royal pain in the A** once you pulled the heads.

There is almost always more than one way to skin a cat.

Yeah I've pulled my watercooled VW engines like that many times. That IFS, with the oil pan in front of the subframe or axle if you will. I'm guessing that this technique is more challenging when you have a SFA in the way.

 

[thechief86]

Never on a 4.0, maybe a dozen times on other engines.

You can get to the other freeze plugs with relative ease, and they make tools for driving them in at weird angles.

We used to replace the camshafts in Volvos with the Peugeot/Fiat/Volvo POS V6 (same engine in a Delorean). Used to use a hole saw on the firewall after removing the dash, then close them up with a couple of body plugs. Of course those are wet sleeve engines and a royal pain in the A** once you pulled the heads.

There is almost always more than one way to skin a cat.

growing up a guy in my neighborhood had a delorean with a v8 in it... was that not the original motor?
also, i've used bar's leaks block sealer and head gasket repair. it sounds like a b.s. bandaid fix, but i've done it to a couple cherokees, a chevy van, a cadillac with the northstar, and a ford taurus. several of them have been running for over 5 years now (caddy, van, and cherokee), and the rest are all still running strong.

 

[Markos]

growing up a guy in my neighborhood had a delorean with a v8 in it... was that not the original motor?
also, i've used bar's leaks block sealer and head gasket repair. it sounds like a b.s. bandaid fix, but i've done it to a couple cherokees, a chevy van, a cadillac with the northstar, and a ford taurus. several of them have been running for over 5 years now (caddy, van, and cherokee), and the rest are all still running strong.

I'm seriously considering a sealer until I have the time to do this repair. It should be a few weeks at most. In fact, I already stopped by checkers and picked up a rubber expansion plug, along with a brass one. I'm literally right in the middle of a move, with the truck rented for this Saturday and Sunday. I have no qualms about doing this myself, but the timing is way off.

FYI - I called a local repair shop (also on ). The estimate was around $700 to do the gasket and freeze plugs. Seems pretty fair given the amount of labor.

My thought is to pickup a $100 HF 880lb electric hoist to help with the head removal. I know it's not that heavy but I need an excuse to buy the hoist. I'll probaly pickup a replacement manifold and add the M.O.R.E. mounts while I'm in there.

 

[Markos]

Confirmed cylinder head freeze plug. I think I'm going to try to patch it with something for a few weeks.