Mike,

Michael's comment about running 100% anti-freeze was because doing so degrades the overheat and freeze protection compared to a 50/50 mix. Running 100% put your engine more at risk for freezing than it would have been otherwise. This could have led to problems thereafter.

If you don't mind me asking, where are you located. From your handle, I would suspect that you might be in northern Ohio, and if that's the case, you're not far from me. I might be able to come listen to it sometime and offer thoughts. I had a 2.3 in an '86 a while back that was the source of fun and amusement.

James

I suspect the bad head gasket, cracked head and/or cracked block caused the freeze plug to let go by letting compression into the water passages. I would go farther and say that the bad head gasket caused the freeze plug to let go and the resulting overheat caused the head to crack and maybe the block too. These blocks don't crack very often. You might get them to warp if you get them really really hot. I half suspect this might be your problem. You need a machinists straightedge and some feeler gauges to measure it.

Chasing the threads is good, but you have to also blow them out with compressed air or something like brake clean to float the grunge from the bottom of the hole. Chasing gets you clean threads, but if the bolts bottom out before properly torquing the head, it is for naught.

As for the sound, I don't know. It might be a problem, it might not. I do not know. It could be something like the check valve on the AIR rail over the exhaust manifold.

As I said before, you need to put some man made pressure into the cylinders so you can see where it comes out. It can exit the block, enter the coolant passages or escape into the crank case. Spinning the engine will not tell you where it is going.

What compression numbers are you getting?

Michael

To go back to the simple things:

1) Is the compression gauge well seated into the sparkplug hole? Does it seal with an o-ring? Is the o-ring in place? Is the o-ring in good condition.

2) Some of the sound you are hearing *may* be just the inherent slack that exists in an engine. 20 year old engines have more slack. By the time you add up the tiny bits of slop in the mains, the rods and the pins, sometimes it makes a lot of noise. I blew a gasket way back when and the darn thing sounded like it had a bad case of rod knock. That is with the bottom end being good in retrospect, but the free spinning of 3 pistons and the resistance (gauge) on one can make things rattle.

3) What did (does) the oil look like? Did it ever get milky? Does it have a pretty sparkle to it? Chunks? We are back to assuming the top end is OK and there is something in the bottom end. A cracked block will not make noise (per say), but a toasted (like really toasted) rod bearing or wrist pin might. (I am really stretching here for ya).

Again, share the compression numbers you are getting. They should not be the same as before a head job and a new gasket unless you are a) really unlucky b) you are doing something wrong when you are doing the compression test.

Good Luck,
Michael

Bought a 3.2 Amigo cheap because it had a cracked head that the dealer's mechanic could not find. A mystery problem on a used car they were tired of dealing with = cheap sale. Turns out the head had cracked across the number 2 spark plug hole's threaded part close to the cylinder. Gas would go out around the spark plug into the cooling system, water did not get in. It took about a half hour of running before the temperature would start swinging from the radiator blowing empty. Only reason I finally found it was I spotted green condensate on the valve cover under the coil one day after it overheated. When I pulled the coil, all I could see in the spark plug well was a little moisture on the tube. Maybe your head has cracked across this same area? Did you try pressuring up the water side of the head while you had it off?

Hi,

I haven't dealt with this trooper in a while. Working 2 jobs keeps me busy. I need to get it running again and soon. I have since gottten a 17 GAL air compressor and a cylinder leak down tester. I took the head bolts out 1 at a time and shot some compressed air down the bolt holes. I left the cylinder head in place when I did this. Nothing came out of the bolt hole through the cylinder head. I torqued everthing back up and the problem persists. The sound that the trooper makes when I spin the engine to check the compression is like a "ka-poo" sound. The sound is in rythum to the spinning of the engine. The trooper makes this sound when I am checking the compression of the 2 cylinders that have very low compression. When I first drained the oil out of the trooper when I first started this project the oil looked like "green slime". I didn't want to gum anything up when the head gasket was leaking so I DID NOT use any kind of stop-leak in the engine. I have done this repair on the other trooper we have here with good results. Does this look like a cracked engine block???? How can I check for a cracked block??? I am at a loss as to where I am losing the engine compression.

Thanks for any help you can give me.


Respectfully,


Mike

Reading this thread is very frustrating.

There are a lots of guys that have been trying to help you out here, giving you some great advice, spending their time thinking about your issue.

It would seem to me that you are choosing not to follow their advice, or you have done what they have said and have not posted the results of the wet compression and /or the leak down test.

These guys KNOW what they are talking about, one even offered to come give you a hand if you were near him.

Your next post on this subject should be some results of the leak down test or wet compression test. If you don't understand the tests then please ask for more details about them.

We get that this is irritating and you don't know what the sound is being caused by, but the sound is not the problem it is a symptom of the problem, do the proper tests to find the real problem.

These engines are pretty darn reliable unless they are treated badly. It sounds like the former owner didn't take care of the problem that had caused the freeze plug to pop, a problem that by the sounds of it builds up an EXTREME amount of pressure in the coolant.

I understand that you really don't want to remove the entire engine but don't stress about it, these engines come out easy.

Please do your tests and post the results so that we can help you.

Congrats on the compressor, they come in REALLY handy.

Wow, 13 months later...

I will agree with what was said above. You are wasting your time (and our advice) by doing things that have nothing to do with a) diagnosing the problem or b) fixing the problem.

Pulling head bolts and blowing air into them means NOTHING. You have determined you have low compression in two cylinders. That is the extent of the diagnosis. A lead down is nice, but who cares. It won't change the next step of pulling the head. It does not matter if it is the head, the valves, the gasket or the block, but the next thing that must happen is for the head to come off the block.

I do wish you luck. I don't know what answer you are looking for, but this thing needs to be torn down. As stated above, the more common problems in these engines are the gasket burning between two cylinders and valves burning. After that I would say a crack in the head is next with a cracked block being last. But, you can know what the problem is without looking at it.

Michael

Hi,

I took the cylinder head back off of the engine to have it tested one more time. The cylinder head checks out good. I haven't touched this trooper for quite some time. I am working on this trooper in the driveway. I don't have a shop where I can pull the engine out. I have given the problem a lot of thought over the last 6 to 9 months. I don't hear any rattling or clanking when I spin the engine.

This engine sat for almost 3 years after the cylinder head cracked. Is it possible that the engine seals and piston rings "dried out" from the anti-freeze and for sitting for so long??????? I was running straight anti-freeze when the engine died. If the compression rings have "dried out" is there something that I can put down the cylinders to "re-lubricate" the compression rings and bring them "back to life"??????

It is not my intention to irritate anyone here. My resources and equipment are limited. I am working on this trooper in the driveway and I am at the mercy of mother nature. I am in Maryland and I am in the open with the trooper in the driveway. I have kept the engine covered with plastic this whole time. this engine only has 165,000 miles on it. I did try to do the leakdown test but to be honest with everyone I wasn't sure what I was doing with the test. I was hoping that the sound I am hearing when I check the compression would ring a bell with someone here. I have had many troopers before and I have never hear this sound before. I don't have the facilities or the resources to put a new engine in the trooper even if I could find one. I am just trying to work with the engine that I have.

If anyone could please help me it would be great. I like my trooper and if I don't get it going soon I am going to have to junk it. Thanks. Help help help.


Mike

You can't junk it! You've been working on this thing for over 2 years now. What would we do if we did not get your 12mo interval updates. <img src="/forums/images/graemlins/smile.gif" alt="" />

The bottom line is still where it was when you started. You have low compression in several cylinders. Leak down does not matter when you blow numbers like you posted above.

You have two options here. It is either a bottom end problem, which is unlikely in these engines. Or a top end problem. More likely.

If you were running 100% antifreeze, you most likely overheated it and either cracked the or burned out the head gasket when it warped. 100% antifreeze sucks for heat transfer. That is whey they tell you to dilute it with water.

Now you have the head off, you have a few options. What you do depends upon what the cylinders look like. You mentioned rust. Did one or more cylinders have coolant in them? Compression rings don't dry out, but they will rust very nicely when submerged in water. :-) If this is the case, then you have a bigger problem. The most proper way to fix it is to yank the block and let a machine shop clean it up. At this point you are looking at basically a full rebuild.

If the bottom end looks OK, no rust you are probably ok to leave it as is. Usually, these blocks have solid bottom end, you might be OK just going with it.

Now, for the head, it is time to take it to your local friendly machine shop and drop it off. It needs to be inspected. At that point, you will know if it is cracked or if you can do something with it. Best case, a valve job with minor surfacing. Worst case, cracked head and you need to look for a new one. At this point, the most cost effective route would be to source a AMC head. It will come complete and ready to bolt on.

Now, if you have light surface rust in the cylinders, you *might* be able to get away with honing them without pulling the block. This would be a super-cheap last ditch effort with the possibility of failure. <img src="/forums/images/graemlins/smile.gif" alt="" /> Just move the piston in each cylinder to the bottom of its stroke and hone gently what you can get to. The problem with this is you can do it, but you are still going to have to invest money in the head and if the bottom end goes to pot, you will be back to where you are right now without a functioning engine.

A new Isuzu head gasket is completely required if/when you put it back together.

Good Luck, looking forward to your 12 month update. <img src="/forums/images/graemlins/smile.gif" alt="" />

Michael

Hi,

The original head was taken off 3 years ago. It was cracked. I found one in the junkyard and had it tested. It tested good but I was told the valves were bad. The machine shop did a valve job for me when they tested the head and machined it for me as well. I then put the replacement head on the engine. These compression numbers are using the replacement head. I tried 2 new isuzu factory head gaskets and one set of head bolts and the numbers came up the same both times. I took the replacement head back off and had it tested one more time just to be absolutely sure that it wasn't the head that was causing these low compression numbers. The replacement head tested good a second time. The head now sits in the middle of my living room wrapped up waiting to go back onto the engine when I get to the bottom of why I have the low compression numbers. I need to get the engine back together soon or I will be junking the trooper.

When I changed out the oil it was like "green slime". The cylinders look good. The engine turns fine by hand. The top end checks out. How can I tell if there is a problem with the rings??? When I did the compression test I did squirt some wd40 down the cylinder and the compression number came up to around 200 PSI. It then went back down on the next test. The engine "spins" fine. What could be wrong with the bottom end??? How do I check for trouble in the bottom end??? Can the cylinders themselves dry out?? Is there a way to check for a cracked block??? Is it possible for the block to be warped??? The engine has been covered with plastic the whole time since I started working on it.

I have been keeping insurance on the trooper so that I can keep it tagged. I couldn't afford the insurance for a vehicle that I couldn't drive so I turned the tags back into DMV a month ago. If I get sited by the local government here for having a non-tagged vehicle again before I have any hope of getting the trooper fixed I will have to junk it.

I don't have the facilities here to work on the bottom end if it needs to be rebuilt. I would have to have the trooper towed to a garage and fixed. That is not cheap. This bottom end only has 165,000 miles on it.

I don't want to junk the trooper but I may have to unless I find the trouble with this engine. Help help help help.


Mike