Thrown Rod on Isuzu Trooper

I tried inquring about this at the one Usenet Isuzu
newsgroup but am not getting any feedback.

Friends of mine have a 2000, 3.5 Liter, 4-wheel drive,
automatic transmission, Isuzu Trooper. While driving it up a
large hill (really, the foothills of a serious Western
mountain range), the car stopped running. I don't have the
details on this, but subsequently, they had it towed to a
nearby mechanic who works on Isuzus and he said it had
thrown a rod. The car is currently sitting in the lot of
another friend who has some background in auto/truck
mechanics but has not yet had a chance to look at it. I am
going to look under the hood sometime in the near future and
try to verify the thrown rod and destruction of the engine.
The owner said he was a bit remiss about oil changes but did
have them done every 10k miles or one year at least. Some
questions:

-- From my googling, a thrown rod can be very obvious: A
steel rod pushes through the crankcase or engine block. Can
it also be not so obvious? E.g. suppose the rod has
disconnected from the piston head, and it's just banging
around inside the cylinder. The latter scenario presumes the
vehicle was stopped quickly. What else can I look for? I am
not sure I will be able to try to start it up yet.

-- I have been making online inquiries of salvage yards
about (1) used cylinder blocks; (2) used, entire engines.
Dumb question but I'm not quite clear on this point: Does it
matter whether the used engine was attached to a 2WD Isuzu
Trooper? It seems both 2WD and 4WD Troopers, of the same 3.5
Liter engine displacement, are available.

-- I am getting quotes back in the $3k-$4k range but from
yards many states away. Shipping seems pretty reasonable and
common. Has anyone purchased an engine or cylinder block
from several states away? What kind of assurances can I get
about the condition of the engine? One seller so far has
said he has a CarFax report verifying the engine has only
seen 32k miles. I plan to check locally, too.

-- Evidently going up hills in too high a gear can throw a
rod. The high gear translates to low revs but high torque,
stressing, from what I understand, the piston rod,
crankshaft, and associated bearings. Can anyone elaborate
further on this? It might help me to identify whether a rod
was actually thrown.

-- I understand installing a new engine is around a day's
work, maybe less. This so? I am going to try to get a quote
for the labor from my favorite import shop in mind but will
also inquire at the nearest Isuzu dealer. Anything in
particular I should ask them other than: "How much to remove
an old engine and install a second-hand one?"

The owners of this car do an astonishing amount of volunteer
work in animal rescue. They are down to one truck (while
normally having two). Given the circumstances, your
assistance is especially appreciated.

(Honda note: Isuzu has done some business on the trucking
side with Honda.)

 

Put the car in neutral, and find some way of turning the engine over by
hand. If there is a thrown rod or a dropped valve, then you shouldn't be
able to turn it 360º, without hitting some sort of obstruction. Sometimes a
thrown rod will knock a hole in the side of the block, but not always.
Sometimes the big end comes loose and pretzels itself, while the piston
drops into the rotating crankshaft. Sometimes the little end comes loose
instead. Whatever it is, the engine won't "feel right" while you are trying
to turn it over. If you have a compression gauge and the starter works, you
could try that too. An engine with serious internal damage will give very
strange compression test results.

Usually, a thrown rod is a sign to discard the engine, or at least the short
block. A dropped valve can produce similar symptoms, and usually means you
need a new cylinder head. If you are into restoration of antique vehicles,
then maybe you would attempt a repair like that, but not on a six year old
car.

The "too high a gear" theory has some merit, but not with an automatic
transmission. The auto should have shifted into a lower, more appropriate,
gear. Driving for very long at too high rpms can spin a bearing though.
That could have thrown a rod or seized up the crank.

Although I generally "push" my oil change intervals, I do feel that 10k
miles is too much for a passenger car, most of my driving is highway with
full warmup of the engine before I stop, and I use high quality, high price
oil filters. (I have to go 50 miles to get groceries.)

The best place to find out about parts interchangeability, is from a
recycling yard. They have manuals of what fits into what, that are
generally very accurate. Do not assume that all 3.5 liter engines are the
same.

Earle

 

Put the car in neutral, and find some way of turning the engine over by
hand. If there is a thrown rod or a dropped valve, then you shouldn't be
able to turn it 360º, without hitting some sort of obstruction. Sometimes a
thrown rod will knock a hole in the side of the block, but not always.
Sometimes the big end comes loose and pretzels itself, while the piston
drops into the rotating crankshaft. Sometimes the little end comes loose
instead. Whatever it is, the engine won't "feel right" while you are trying
to turn it over. If you have a compression gauge and the starter works, you
could try that too. An engine with serious internal damage will give very
strange compression test results.

Usually, a thrown rod is a sign to discard the engine, or at least the short
block. A dropped valve can produce similar symptoms, and usually means you
need a new cylinder head. If you are into restoration of antique vehicles,
then maybe you would attempt a repair like that, but not on a six year old
car.

The "too high a gear" theory has some merit, but not with an automatic
transmission. The auto should have shifted into a lower, more appropriate,
gear. Driving for very long at too high rpms can spin a bearing though.
That could have thrown a rod or seized up the crank.

Although I generally "push" my oil change intervals, I do feel that 10k
miles is too much for a passenger car, most of my driving is highway with
full warmup of the engine before I stop, and I use high quality, high price
oil filters. (I have to go 50 miles to get groceries.)

The best place to find out about parts interchangeability, is from a
recycling yard. They have manuals of what fits into what, that are
generally very accurate. Do not assume that all 3.5 liter engines are the
same.

Earle

 

Are these a Isuzu engine or rather the Buick V6 that went into some of
them?

May be better to dump it to someone who wants to do an engine swap.

 

Are these a Isuzu engine or rather the Buick V6 that went into some of
them?

May be better to dump it to someone who wants to do an engine swap.

 

Earle, wow, this strikes me as a fabulously informative
post. I will explore all you said as my access to the truck
allows. I won't be doing any of the restoring myself; this
is for my education and hopefully to provide these folks
with some assistance. Thank you.

 

Earle, wow, this strikes me as a fabulously informative
post. I will explore all you said as my access to the truck
allows. I won't be doing any of the restoring myself; this
is for my education and hopefully to provide these folks
with some assistance. Thank you.

 

when it throws, it usually throws violently, i.e. through something. if
you can see the engine clearly, that should be detectable. if the motor
runs and ejection is not obvious, look for other clues like a mysterious
"misfire". i once had a vehicle come in with "a strange oil leak". the
guys said: "every time we fill with oil, it disappears again. it's
leaking out somewhere, but we can't see where. oh, and it's got a
slight misfire." it sure did, it was running on 5 cylinders with the
6th thrown out into the engine bay.

what about jdm imports?

not on its own.

"lugging" [too low revs] can cause fatigue which will throw a rod when a
cap bolt fails, but over-revving will do the job just as effectively and
is much more common. or it's just a substandard cap bolt. lugging is
most unlikely if the vehicle's automatic.

 

when it throws, it usually throws violently, i.e. through something. if
you can see the engine clearly, that should be detectable. if the motor
runs and ejection is not obvious, look for other clues like a mysterious
"misfire". i once had a vehicle come in with "a strange oil leak". the
guys said: "every time we fill with oil, it disappears again. it's
leaking out somewhere, but we can't see where. oh, and it's got a
slight misfire." it sure did, it was running on 5 cylinders with the
6th thrown out into the engine bay.

what about jdm imports?

not on its own.

"lugging" [too low revs] can cause fatigue which will throw a rod when a
cap bolt fails, but over-revving will do the job just as effectively and
is much more common. or it's just a substandard cap bolt. lugging is
most unlikely if the vehicle's automatic.

 

-------------------------------------------

Yes,

IF you have air tools, a hoist, maybe a crane, and any 'special' tools
the MAKER dreamed up for holding their engine in place. Otherwise you
spend half a day driving around town trying to find some %#*!#@
left-handed needle-nose *&%#$! thingy that holds the _____________ on.

Keep that in mind.

'Curly'

 

-------------------------------------------

Yes,

IF you have air tools, a hoist, maybe a crane, and any 'special' tools
the MAKER dreamed up for holding their engine in place. Otherwise you
spend half a day driving around town trying to find some %#*!#@
left-handed needle-nose *&%#$! thingy that holds the _____________ on.

Keep that in mind.

'Curly'

 

Bad mojo! I have only seen two thrown rods personally, and both times the
rod came through the crankcase but was not sticking out. I don't think
that's always true. In both cases (a Subaru and a Toyota) the engine was
pretty worn and had known oil pressure problems that were not worth tracking
down in so old a car. In each of those the diagnosis wasn't hard because
there were pieces of crankcase on the ground under the engine, which seemed
somewhat irregular....

One caveat on the engine swap - don't forget to address the problem of
dealing with the refrigerant if the vehicle has A/C. Maybe the compressor
will swing out of the way and the hoses won't be threaded through anything
important, but when was the last time you were so lucky?

Mike

 

Bad mojo! I have only seen two thrown rods personally, and both times the
rod came through the crankcase but was not sticking out. I don't think
that's always true. In both cases (a Subaru and a Toyota) the engine was
pretty worn and had known oil pressure problems that were not worth tracking
down in so old a car. In each of those the diagnosis wasn't hard because
there were pieces of crankcase on the ground under the engine, which seemed
somewhat irregular....

One caveat on the engine swap - don't forget to address the problem of
dealing with the refrigerant if the vehicle has A/C. Maybe the compressor
will swing out of the way and the hoses won't be threaded through anything
important, but when was the last time you were so lucky?

Mike

 

I will double check that the shop that the owners of this
Isuzu Trooper truck use are well-prepared to do an engine
swap, if it comes to this.

I was mostly curious as to how long it might be before the
owners get the truck back.

I wish I could get my hands on the changeout part a little,
but I hesitate to do even minor work on other people's cars
(too much liability, emotional and financial). Plus, as you
suggest, I have nothing like the special tools that are
needed. Those little hoists/cranes that lift the engines out
look like fun. Such "possibility."

One interesting thing I learned from the several engine
salvage yards that responded to my query is that many list
on their web sites the cost of a refurbished 91 Civic (my
car) engine. It's typically around only $600, including
various warranties. At least, $600 seems cheap to me.

 

I will double check that the shop that the owners of this
Isuzu Trooper truck use are well-prepared to do an engine
swap, if it comes to this.

I was mostly curious as to how long it might be before the
owners get the truck back.

I wish I could get my hands on the changeout part a little,
but I hesitate to do even minor work on other people's cars
(too much liability, emotional and financial). Plus, as you
suggest, I have nothing like the special tools that are
needed. Those little hoists/cranes that lift the engines out
look like fun. Such "possibility."

One interesting thing I learned from the several engine
salvage yards that responded to my query is that many list
on their web sites the cost of a refurbished 91 Civic (my
car) engine. It's typically around only $600, including
various warranties. At least, $600 seems cheap to me.

 

Indeed!

This 2000 Isuzu truck has "only" 133k miles on it. But maybe
this is a lot for Isuzus.

These folks may have done some serious towing with it,
wearing bearings prior to this apparent catastrophe. (Sorry
I can't get all the facts just yet.)

I'm not going to attempt this myself. I wanted to know on
what to keep an eye with any shop that does the job.

Thanks for the input, Michael.

I'll update if I or someone else ever gets access to the
truck.

 

Indeed!

This 2000 Isuzu truck has "only" 133k miles on it. But maybe
this is a lot for Isuzus.

These folks may have done some serious towing with it,
wearing bearings prior to this apparent catastrophe. (Sorry
I can't get all the facts just yet.)

I'm not going to attempt this myself. I wanted to know on
what to keep an eye with any shop that does the job.

Thanks for the input, Michael.

I'll update if I or someone else ever gets access to the
truck.