I am the proud owner of a 1992 4WD pickup with a 4ZE1 that at 170K km decided it was time to blow the head gasket at cylinder #4.

I have baby'd this stock engine and am a little surprised.

The manifold bolt at #4 broke several years ago (which I know is common as this is my second ZU) and I have had some minor leakage of oil/antifreeze(?) below the #4 cylinder for about 3 years.

I have yet to remove the engine for a rebuild and am wondering if the #4 cylinder on these engines are prone to head cracks? Would the history of these engines provide any insight into what I can expect when I tear it apart.

Also, if you have some tips on engine removal I would appreciate hearing your experiences.

Thx, J

Well first I have tons of pics of my 4ze1 rebuild on my web shots pages.
http://community.webshots.com/user/boblarge34
http://community.webshots.com/user/boblarge35

As for the head cracks. Yes I have heard that some of the 2.6 (stock) heads do have a tendency to crack. But IÆm not sure what cast numbers they are. You might want to do some searching. There are tons of good posts on 2.6 head issues.

As for removal. You really wonÆt need to pull the block if you are not planning on rebuilding the bottom end / piston/rings.

But if I had to guess I would say that you just blew a head gasket. That would account for the oil/coolant mixing. And thatÆs shouldnÆt be too hard to fix. Pull the head bolts and prop the head/intake up 4" or 5". Then clean up the mounting surface of the block and the head. Make sure there is no oil on the surfaces then put the gasket in and carefully mount the head. Tighten all the head bolts to spec and your off and running.

That's where mine went too... at about 90K miles, which I think is roughly equivalent to 170K Km ...



I doubt that you will gain anything by rebuilding the entire engine. Did you burn any oil prior to the gasket failure ? After I did the head on my engine, my compression was 173 pounds on all 4 cylinders... in fact, you could still see some evidence of the "cross-hatch" marks from the cylinder honing. There was virtually NO ridge at the top of the cylinders. No, save yer money on a complete rebuild.

Look on the backside of the head with a mirror, (or if it's apart, just look at it). It should be embossed with 4ZE1 , and a number. If you have a 3, 4, or 5 casting, you probably don't have any cracks, but it would be a good idea to have the head re-worked. A valve job, and "flattened". If you've got a 1 or 2 casting, you might consider a new head by AMC or Pro-Topline.

There are two "dowel pins" that locate the head on the block, and there have been reports that these may be partially responsible for this type of failure. It seems that in some cases, either the pin is too long, or the relief cut in the head and/or block are too shallow to allow the head to fully seat on the gasket. In other words, they hold the head up above the block deck just enough to cause a failure after quite a few miles.

As a precaution, shorten them dowel pins down a bit before putting it back together!

Do NOT use an el cheapo head gasket! Use only OEM or Fel-Pro product. Jerry Lemond jlemond@bellsouth.net can supply the OEM at a good price.

The head is removed with the intake manifold attached. You can also leave the exhaust manifold on, but it is possible to un-bolt the exhaust mani and wire it back far enough to get the head off.

Search the archives for a post by "Rufus The Ram" who did a write-up a year or so ago. It gives a "step by step" on pulling the head.

Good Luck!

My friend's 1989 pup blew the head gasket between #3 and #4 cylinder. He gave the truck to me and I decided to rebuilt the whole engine. I took the head to a shop to have it pressure test, replace valves and seals and shave. I put everything back with the delta cam. 2000 miles later the head cracked on the exhaust side around cylinder #4. I think the head was a number 3. I bought the AMC head and everything is fine 'til now. If you're thinking about rebuilding the old head, I would recommend just get an aftermarket head instead.

In general I agree about replacing the head, but the later ones were not that bad. If you've got a 5, think long and hard about whether or not you want to replace it with a new one...

Lor, your crack issue _could_ be related to the "dowel pin syndrome" . ESPECIALLY since the head was shaved. That pin is located on the exhaust side of the #4 cylinder. If the head was sitting on the pin, well... you know the rest!

In any event, before torquing the head down, I would recommend putting some "plasti-gage" in the relief on the head, where the dowel pin sits, and place the head on the block _without_ a head gasket. Put a feeler gauge between the head and block near the dowel pin to make sure it's seated. Remove the head and check the plasti-gage to be certain you have clearance. Remember that without the head gasket, if you have clearance on the pin, you will surely have clearance with the gasket installed.

Thank everyone for the help!

I am just taking it apart and will get back on what I find.

J