Would someone PLEASE explain, once and for all...

[Zaphod]

... WHAT, exactly, the problems are with the 3.5L V-6 engine and 4L30 transmission found in my beloved 2000 Trooper LS?

Concerning the engine:

I've heard the cylinders are too big for the pistons, or that the pistons are too small for the cylinders. I've heard that the rings suck. I've heard there aren't enough holes drilled in the pistons or in some other part(s).

Which is it?

Then... what's the best way to FIX it? I am not going to get rid of this vehicle, and if I have to replace or rebuild the engine then I'll do it, but I want to know if rebuilding an engine is someone with minimal mechanic experience (but who is pretty handy otherwise), a copy of the appropriate Helm Manual, and some time can pull off? If I replace it, am I replacing the entire thing, or just part of it? I've heard the term "Short Block" thrown about, but I don't know what that is. I guess I was on the Short BUS when it came time to learn auto mechanics.

Concerning the transmission:

I've heard more than one person post that they're on their 2nd, 3rd, and even 4th transmission. Interestingly, some of these same folks have been very please with the results after they installed additional coolers. How complicated is that (I've heard as little as 2 hours), and how does it avoid the problem (other than the obvious)? Also, if my tranny has 95K trouble-free miles on it, should I consider replacing it if I take the plunge and do the engine, AND THEN install a cooler anyway?

So you see, what I'm looking for is the drop-dead skinny on these two issues, and what the viable options are. If I have to rip this puppy apart, I want to know what I'm getting into in advance and how long my garage is going to look like the aftermath of an IED.

Thanks in advance. I'm at my wits end trying to research this myself. I kinda feel like this guy: :REOutShootinghunter

 

[jl8088]

i know about your issues as i've been reading up about them too.

ENGINE:
I believe that all 1998- some month in 2000 troopers had an issue with their rings on the pistons. It didn't allow enough oil back down to the crankshaft and burns up the oil. They fixed the ring design on newer 2000+ models. Apart from replacing the rings, i'm just going to keep a careful eye on my oil level and try the Rotella oil 5w30 or 0w30 oil which has cleaners in the oil which overtime will reduce the carbon deposits on the rings. I'll also be trying seafom treatment right before the oil changes to get all the carbon junk in the engine out. Over time, this will hopefully clean up the engine and reduce the oil burning to more manageable levels. I wouldn't open up the engine to fix this, unless you've got the time/ability to do this easily, but don't let me stop you.

Tranny:

From all that i've read, the 4L30 tranny isn't too bad. I've heard it likes its fluid changed every 15K miles. I'll be doing this and because i've got 95K i'm going with the drain and refill method as opposed to a power flush. I've heard the horror stories about people on their 2nd or 3rd tranny. That's scary, but i believe these guys are heavily wheeling their cars, so abuse can only hold up for so long. I'm really concerned about mine as my trooper is generally used for trails. I'm toying with the idea of the external cooler too. It would be cheap (under 200) and coundn't hurt right? I've heard bad things about improperly installed coolers leaking fluid and overheating the tranny too, so make sure you do it right. I believe companies like Hayden make external tranny coolers.

I had to clean my range indicator recently and it made one hell of a difference in my tranny shifting. I'd suggest doing that if you haven't already as preventative maintence.

Anyhow, that's my .02 from what i've read, let me know if you have anymore insight and end up doing the tranny cooler.

Trails a callin'

Here is the dirty range indicator that was giving me some shifting problems.

here it is cleaned up

TRAIL TIME!!!

 

[DBS311]

I believe that on the pre-2001 Troopers, there were only 2 oil ports/drains on the piston while the newer 3.5's got 4. This keeps the oil in the combustion chamber and it gets burned up rather than draining back down. That is the "simplest" way I can explain it. Piston and rings would need to be replaced. This would be quite an undertaking for someone with little experience, but nothing is impossible. The key factor for doing any work on a car is having the correct tools, and most of what you would need could be rented. Some things you would want to have a proper machine shop handle, like honing the bores or machining the heads. A short block is basically the block, crank, rods and pistons all pre-assembled. You would have to put all the other components on yourself, which isn't a bad deal. If you are attempting to do a lot of the work on your own, and don't have much experience, this very well could be the best path to choose.

As far as replacing the tranny, I would drop the pan/drain the fluid first and take a look. No reason to replace the tranny if it is operating properly. And yes, I would add a cooler while changing the fluid. Personally, I like B&M fluid coolers, especially the ones with a built in temp sensor and fan. This really helps while creeping at slow speeds on the trail.

 

[madizell]

Two posts have mentioned that the piston and/or ring design didn't let enough oil back down to the crank shaft or whatever, and so gets burned up. Someone is going to have to explain this to me.

Pistons on 4 stroke motors have two kinds of rings 1) combustion/compression rings; and 2) oil scrapers/seals. Compression rings keep exhaust gases up top, above the top ring line, and oil rings keep oil below the top-most oil ring -- scrapers scrape off excess oil and push it back down the piston wall, and the seals keep the rest from migrating any farther than the seal. The oil does not come from above the rings and thus is not "kept" there, nor does oil somehow make its way down from the top of the piston to lubricate the crankshaft (cranks being lubricated by pressurized passage direct from the oil pump). If your engine consumes oil and it is because of ring by-pass, the common culprit is the oil seal ring set, which is made up of 3 parts, two very thin seal rings help apart by a separator ring that looks like a waffle or ruffle. Generally it is the separator that fails due to wear or breakage, or the seal rings can lack or lose tension in which case they don't stay tight against the cylinder wall. Once oil passes the oil seal rings, it will be consumed in combustion because the compression rings are designed to keep pressure above them, not to stop migrating oil from below. Actually, all engines consume some oil in this manner, which is both normal and necessary to keep these parts alive. What constitutes "excessive" oil consumption is an engineering determination. Rings malfunction when the amount of oil consumed exceeds an acceptable range.

If the problem with the piston design is that it didn't have sufficient oil drain passages, these would be located in the groove of the oil scrapers, hidden behind the oil rings. It is possible I suppose that these ports do remove accumulated oil from the ring groove, but I don't believe that they are primarily intended for the purpose. I always thought that the purpose of the ports was to place oil under the dome of the piston for cooling purposes and, perhaps, to provide a bit of oil for the piston wrist pin which only gets splash lubrication. Oil otherwise trapped on the walls of the piston and below the oil scrappers simply provides lubrication to the piston which would otherwise gall and seize.

Isuzu has had many problems in the past few years with quality of the product, and the Isuzu dealership I know about in Anchorage kept itself busy day in, day out, replacing motors and transmissions under warranty. These were simple daily drivers and soccer moms, not hard core off roaders. Just about no one in Alaska uses the Isuzu for off road.

I would say if yours is working at 95K miles, keep driving it, keep maintaining it, and stop worrying about it. If it was a lemon it would have been lemonade by this time.

 

[Zaphod]

Oh, and they're built in France which has its own set of connotations entirely.. :shakin:

LOL. Yeah, you ain't kiddin'!


Thank you all for great answers.

Madizell, I certainly understand your take on the leave-it-if-it's-working idea, but there is a part of me deep down inside that wants to be completely comfortable with this vehicle in a daily-driver scenario, an off-road scenario, and even a SHTF scenario. With that in mind (and since I need to do it anyway), I am leaning toward DBS's advice on the transmission (open, inspect, flush, install cooler, and leave it otherwise). As for the engine itself, I am going to try a "super" flush using both motor flush/seafoam, and THEN taking it to a decent mechanic to see if they have a "professional" flush. I've heard that in some cases such a flush, combined with the use of synthetic oil, has greatly reduced the oil consumption issue.

Of course, I'll also be having that shop replace the timing belt, water pump, and anything else they find.

Sigh.... I really wish I had a real garage right now so I could do this stuff myself and learn how to do it. Oh, well. Next time.

Back to you, Madizell. I recognize that "excessive" oil loss is a bit subjective, but I am definitely burning more than I should be. If it's not rings and pistons, and if I am having no oil leaks anywhere (I'm not) then what else could be causing it?

JL,

Where is that pert you have shown above located? I wouldn't mind checking mine in light of that occasional over-rev I experience from time to time...

 

[madizell]

LOL. If it's not rings and pistons, and if I am having no oil leaks anywhere (I'm not) then what else could be causing it?

Oil consumption can be attributed to ring by-pass, as discussed, or valve guides. A compression test can help indicate ring condition, but a broken, worn, or otherwise defective oil ring will cause consumption without affecting compression. Also possible is cylinder wear or damage, sometimes caused by ingested debris, high dirt content in the intake stream, piston scuffing, whatever. A gouge or scratch in the cylinder wall will allow oil to pass and be burned, although this type of flaw will also generally reduce compression.

Not sure how an engine flush can decrease oil consumption unless the piston rings are totally gummed up to the point of sticking, and a flush cleans out the gum allowing rings to reseal. Detergent content in modern motor oil and gasoline has pretty much eliminated heavy carbon deposits and oil residues, so long as you change oil regularly. Worth a try, I suppose.

BTW, how much oil do you consume in, say, 3,000 miles? Can you see visible smoke while warmed up and running? Any puff of smoke on cold start-up? Are you spark plugs black and oily? Does your chewing gum lose its flavor on the bedpost overnight?

 

[Zaphod]

BTW, how much oil do you consume in, say, 3,000 miles? Can you see visible smoke while warmed up and running? Any puff of smoke on cold start-up? Are you spark plugs black and oily?

It varies. It seems that on the highway it burns more than driving around town, and I think cold weather may be a factor.

Case in point: I drove from Laredo, Texas to Durham, NC non-stop. The oil was changed and topped off 15 minutes before I began the drive. When I got to western NC, I was 4 quarts low.

I did have LOTS of white smoke/steam the other day after the truck had sat unrun for almost 2 weeks, but nothing I've noticed otherwise. Last I looked at the spark plugs, they were fine.

Does your chewing gum lose its flavor on the bedpost overnight?

Does your tobacco taste different lately? :bigbossHL: :ylsmoke:

:xxrotflma

 

[madizell]

Well, 4 quarts is excessive an anyone's book. If it does not generally do this with shorter trips but of the same accumulated miles, it sounds like the engine pumps up at speed, which would indicate one or both of two things: loss of compression past the rings into the crankcase causing excess internal pressures which will force oil past rings and valve guides and eventually gaskets and seals; or little or no crankcase ventilation which allows normal amounts of pressure to build up rather than to be dissipated.

White smoke is one thing, steam another. If you really had steam in the exhaust after sitting for a couple of weeks, you have a compromised head gasket (most likely) or a crack somewhere in the block or head allowing coolant to escape. Does your coolant level drop such that you have to keep topping up the system, or can you find oil residue in the radiator or overflow tank? Water leaks don't generally come and go, and they never just get better. A compromised head gasket can account for both water and oil to be leaked into one of the cylinders, in which case one of your spark plugs will look quite different from the rest.

Lots of white smoke after sitting around for a while suggests oil migration past the valve guides. Only one way to fix that. Rebuild the heads.

In any case it sounds to me as if you are looking at an engine overhaul. You can try the motor flush, it will either help or it won't, but I would not expect it to remedy a 4-quart highway consumption problem or steam and/or smoke from a storage start-up by adding a cleaner to the crankcase.

 

[madizell]

Way back in about 1974 I bought a 1949 Willys CJ2-A with the L-head motor, from a farmer who thought it was some kind of farm weapon that didn't need maintenance. Drove it 35 miles home, and used 5 quarts of oil and had hot oil pressure of somewhere around 5 pounds. It had other issues as well.

The pistons and rings were worn so badly you could see daylight past the rings, and the valves rocked around in the guides like straws in a glass of Coke. There was a wear groove at the top of the cylinder nearly 1/16 inch deep. I rebuilt the heads myself (which I would not attempt again today, but I was 24 back then), and found pistons and rings .080 oversize from JCW. No one else sold parts that far over standard. Replaced the rod bearings without doing anything else to the crank. Didn't have the money to have the block bored so I honed it by hand with a deglazing hone, and when done, at least one point in the cylinder had clearance that was about right, otherwise there was a lot of taper. All the parts cost $75 from JCW.

But, when done, the motor ran well, had 60 pounds of oil pressure, didn't smoke, and got 3,000 miles of use without adding a quart of oil. Sounds like your engine is getting close to where mine was, and needs to be rebuilt or replaced. Long blocks are generally cheaper than doing rebuilds.

 

[jl8088]

per Isuzu, 1qt of oil per 1000 miles is standard usage.

 

[madizell]

1 quart in 1,000 miles is corporate butt covering. If, in fact, the corporation thinks that is a normal and acceptable engineering standard, then they are admitting to building junk motors. Instead, I think it is their way of trying to avoiding endless warranty claims by convincing innocent owners that their "problem" isn't a problem at all. All of which tends to explain why the company is fading from the market.

 

[endo]

1 quart in 1,000 miles is corporate butt covering. If, in fact, the corporation thinks that is a normal and acceptable engineering standard, then they are admitting to building junk motors. Instead, I think it is their way of trying to avoiding endless warranty claims by convincing innocent owners that their "problem" isn't a problem at all. All of which tends to explain why the company is fading from the market.

While I will agree that it is bunk to say that it is acceptable for a company to claim 1 qt over 1000 miles of consumed oil is with in "spec" Isuzu is not by any means "fading from the market" they have removed themselves from the light truck and SUV market but they are one of the largest manufactures of large trucks and more importantly diesel powerplants (duramax). Don't brand bash, I agreed with everything you said until the last sentence.

ROFSheriffHL:

 

[endo]

oh and to add to the discussion my 2000 burns WAY to much oil. But it only smokes above 3500 rpm while @ WOT.
Dont ask me...
However Lucas oil products seem to keep it somewhat in check.

 

[Zaphod]

Does your coolant level drop such that you have to keep topping up the system, or can you find oil residue in the radiator or overflow tank?

Negative on both counts, as far as I can tell. I've never had a coolant issue that I've noticed, but I WILL be looking in the overflow tank with this in mind, now that you've mentioned it.

A compromised head gasket can account for both water and oil to be leaked into one of the cylinders, in which case one of your spark plugs will look quite different from the rest.

I'll check that, too.

Lots of white smoke after sitting around for a while suggests oil migration past the valve guides. Only one way to fix that. Rebuild the heads.

In any case it sounds to me as if you are looking at an engine overhaul.

Yikes.

What I wish I could remember is if the "smoke" dissipated quickly (which would be steam), or hung around a little longer (indicating smoke). Frankly, I remember it looking like steam. It was one hell of a cold day out, and the truck hadn't moved in at least 10 days.

Either way, though.... It don't sound good.

 

[Zaphod]

Sounds like your engine is getting close to where mine was, and needs to be rebuilt or replaced.

Just for ****s and giggles, let's assume that you're right.

If I can find a reputable mechanic (no way in hell I'm going to a dealership on this unless I am strongly urged to do so by those in the know), what do I ask them to look for, examine, etc.? I don't want them disassembling the engine if it's not needed.

I just wish I knew more about this stuff. Pisses me off to be so clueless about it.

Long blocks are generally cheaper than doing rebuilds.

The long block is everything from the oil pan up to the cylinder heads, correct? I'm one of these weirdos who, for better or worse, feels better just replacing the whole damned engine than having to worry if they rebuilt it correctly....

Where would you recommend obtaining a new long block that will have all the necessary adjustments and upgrades present?

Thanks again for the great answers. I'm not worried about bad news; I just need ACCURATE info.