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48 Posts
Discussion Starter · #1 ·
:cry: :shock: :oops:
Someone, please, answer this post.......My beloved 1990 Trooper had a rebuilt engine installed in August. Last week, it started missing, then no heat, but still had antifreeze......we immediately stopped driving it and had the [Chevy] dealer who ordered the rebuilt engine take it back into the shop. Latest word is that coolant was in the plugs, and to make a long story short, before sending the engine back to the company the dealership bought it from, the dealership is looking inside the engine to see if they can determine why this happened........Now I already know that the rebuilt engines {4ZE1} have a little 'spot' and the back of the head that will tell if the engine overheated......I'm not real worried that we did anything wrong, but rather, my concern is.....

How often does this happen?????? Is this model engine really as bad as it seems? I love this Trooper and I don't want to have some other car; but I am concerned....Are these 4ZE1 engines super delicate or something?

Is the only resort to buy a new aluminum head or one with a certain casting number or something?

ANY thoughts on this model engine would be appreciated !!!


· Registered
1,293 Posts
Wow, I can understand if a gasket had failed that you would have coolant in one cylinder, but all four? I would think that's more indicative of a failed block................?

If the head cracked, then it depends on where it cracked and what jacket's were affected. In any case, I would find out who the rebuilder was and get a breakdown on parts used in the rebuild.

I'm not aware of a 'spot' on the rear of the head, but the casting number is there. That would be the first thing to check and see which casting the head is and if it's a reman OEM head or a new head/casting. If it's an OEM head that's been remanned, the number should be at or higher than 4(?)

Maybe someone else will chime in on the casting numbers but as I undersand, the 4 series castings and up are OK UNLESS there is a gasket failure and/or the engine overheats.

The 4ZE1 motors are quite stout and will last several hundreds of thousands of miles, BUT, as with any 4-banger (well, with any motor of course), care must be taken to maintain the cooling and lubrication systems. Unfortunately, the temperature monitoring systems are very inadequate and don't 'audibly' or 'visually' warn of a problem until it's too late - the automotive industry has never figured out that copying the aviation industry in the instrumentation is the best way to go - "All Green Is Good".

ISUZU did have a casting problem with the early 2.6's but the problem was resolved with later issues of the heads.

If you find that the head failed and was a 3 or earlier casting and was installed as an OEM reman, then I would refuse to accept the engine back an demand a new motor from a different builder and then to make sure the head is a NEW head, not a reman - and there are several manufacturers still making heads for this motor.

What was the warranty offered with this rebuild?

Sorry for your troubles, I hope things get worked out. Keep 'em running.


· Registered
48 Posts
Discussion Starter · #3 ·
Thanks for the reply. You reminded me of the casting numbers - I couldn't remember which numbers [hadn't taken the time yet to look it up].

Well, as to the 'spot' I have seen them, even on the Isuzu motor. When I have a moment, I'll look it up on another Isuzu website which shows a photo. This spot is supposed to change from when it was manufactured, IF, that is IF, the engine overheated.

Good idea about breakdown on parts used, I'll mention it to the dealer shop supervisor. This is a small dealership, in a rural area, with a long history of faithful service. So far they've been real good with the Trooper, though I've had to mention a few things peculiar to Troopers that I've learned from the websites. Usually I'll e mail the info right from the particular websites.

The warranty was 12.000 miles or 1 year.

I'm not ready to throw this Trooper away, Just need patience!
This car is great, it's even won over Mr. Hubby, we now use it on explorations along with our GPS into extreme rural ranch areas of Kansas.
[Near the Ted Turner ranch - beautiful area]

Thanks for your reply.
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