Greetings, folks; I would really appreciate your wisdom!

When I started Rebecca the Raider yesterday morning, she immediately began making a knocking noise I had never heard before. She was last used to stomp a trail in the snow on Saturday; it was the first time I have put her in 4WD this winter, and she laid the tracks easily, going slowly.

She is only used to run into town for water and supplies, about 100 miles per month, and the trail has been easy for the past year. She hasnÆt had to do any real work for three years and I kept her RPMs low even then. She currently has 100,242 miles on her and I had bought her used in 1994 with 48K miles on her.

On the way into town yesterday, the knocking got significantly worse when the engine RPMÆs went up past ~1.4K; the temperature was the usual low setting. No warning lights were on. I got her off the mountain, into the nearest town, and after running errands (in an asphalt-only car), I opened the hood, started her up, and realized immediately that this was a significant problem. She went straight to the nearest and most-trusted repair shop, about eight miles away, keeping the RPMs as low as possible.

She has been going through about a quart of oil every 600 miles and was last topped off 600 miles ago. The shop owner immediately checked the oil as a possible culprit, and she was down about 2 to 2.5 quarts; it should have only been one quart, at most (given the low temperatures), and based on past patterns. Topping the oil off didnÆt stop the knocking.

Based on the knock, she was diagnosed by both shop owners (separately) with:
- a ôworn bottom endö
- a connector rod is hammering on the crankshaft
- the rod bearings are bad
- ôthe bottom end is going outö

I was told that if there was a minimum of three quarts of oil in the engineùwhich I can absolutely verifyùthen a lack of oil was not the problem and I should definitely replace the engine as there was something else that was the problem. They said that she cannot be expected to be able to travel any distance at all without finally ôthrowing a rodö and thus destroying the engine or else the engine will simply just seize. They were amazed I made it back (slowly!) to camp. I have not checked the oil pressure since monitoring the knock and donÆt feel inclined to start her up just to check!; please forgive my carelessness for not logging the oil pressureùthis is all new to me. She will need to go back into town in about ten days.

I have poured through the ôrod knockö search results and found thoughts on rebuilding or replacing the motor, but am not able to do the work myselfùit must be done in the aforementioned shop. Any advice would be greatly appreciated!!

Blessings and thank yet again!,

Richard Fairbanks

It is unusual for the bottom end to go at 100k miles in a 3.0L Mitsubishi engine, but at the rate it's been using oil, there's quite a bit of cylinder wear. I suppose it's possible that the mileage wasn't accurate when you bought it, but not likely if you bought it from someone reputable.

I assume the mechanic looked the engine over carefully. If not, the knocking may be a loose harmonic balancer (crankshaft pulley) - a known issue from improper bolt torque and a bad bolt design - now superceded by a new bolt that is available from dealers for a few dollars. If this isn't the problem (and it probably isn't), the mechanic is probably correct. Further driving in that condition will quickly destroy the engine. The oil consumption rate indicates that it's due for a complete tear-down and rebuild, anyway..... unless the oil is leaking to the outside. Do you see any oil stains under the engine after it's been parked overnight? If so, it's possible that a seal is leaking and you could get by with replacing the seal and some bearings - still not cheap to do.

Judging by the limited mileage, I'd suspect a piston wrist pin issue from lack of use, but it's hard to say without a close look. Either way, a piston/rod/bearing issue is going to be a major expense, so be prepared for some bad news..... up to and including a full rebuild.

Frank

Bless you, Frank! I really appreciate your response!

Some (probably minor) answers to your points:

- The Raider was purchased from a private individual of unknown reputability: he wanted to go to his bank to deposit my cash ($7K in 1994) before signing over the title. He had just bought it from ôa little old lady who drove it to the store and back.ö á á;-)

- The shop had JUST replaced the crankshaft pulley bolt 600 miles ago (as noted HERE )ùthe last time I topped off the oil, etc.

- The oil has been slowly leaking to the outside for years, but never at that rate (2+ quarts in 600 miles) before. It just coats the oil pan, etc., but rarely ends up on the dirt (I am camped out in the remote wilderness). The shop has said in the past that it was common for an engine that old.

If the engine must be completely rebuilt, how much more expensive would it be to find a low-mileage replacement engine? Would that not be the wiser route? As the stock 1989 3L V6 is so old by now, what are the best options? (There must be pages covering that exact issue on hereá.á.á.á)

Thank you!

I ditto that on the harmonic balancer, check that first. Mine as you'll see in a recent post was loose for a long time.
It didn't make a real rod knock sound,more like a loud "TACK,TACK TACK", but it was loud at low rpms untill engine was hot.
Hope thats it, and there's no damage yet.

You probably won't find a low mileage replacement engine.

If you like the truck and want to keep it, your best bet is either a known good used engine (which will probably have 100k miles on it or a rebuild.

If you have your engine rebuilt, there are a few things the mechanic should agree to do:

1) Throw away the book on head bolt torque. Head bolts should be torqued to 80 lb-ft.
2) Clean the deck holes for the head bolts with a bottoming tap and make absolutely certain the head bolts aren't too long to get full clamping force without false torque readings.... let us know if you need instructions on how-to.
3) Use a new and updated harmonic balancer bolt/washer.
4) Don't reduce the combined head and deck thickness more than .008".
5) Check the lower intake manifold for warpage.

If there are other questions, let us know.

Good luck.

Frank

check your torque converter bolts and harmonic balancer

Drain the oil and look for bearing flakes. Cut the oil filter apart and do the same. You can get pipe cutter just for cutting the filter apart that does not leave metal flakes and confuse the issue.

Finding metal flakes will confirm that the motor is hurt.

I rebuilt my v6 a while ago - same engine as yours but in a gen2.

It covers most angles and Frank and other gave valuable input and lessons on the build.

NOTE : imageshack have changed their terms and you have to be logged in to see my images (very dumb I know)

http://www.4x4wire.com/forums/showflat.p...rt=all&vc=1

Folks, thank you so much for your time on this. Please forgive me, but although I am a very technical person and had a very successful production company, I am ABSOLUTELY CLUELESS regarding internal combustion engines. This site has been a critical resource for my belated education! á ;-) á And, before I proceed, please allow me to vent my undying devotion: I will NOT give up my Raider! That girl has bailed my butt out so many times, in such remote locationsá.á.á.á

Please allow me to respond in order of posts:

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Dave and mxmikie, regarding the harmonic balancer:
I went outside, popped the hood, and wrestled with the crankshaft pulley (with the replacement bolt through itùthank you, Larry!). I couldnÆt get it to ôwiggle.ö I also assume that such an effort probably means nothing regarding the security of its mounting. Do you have any suggestions as to how I might be able to tell if the harmonic balancer/crankshaft pulley might be the potential source of the knock?

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Frank, again, thank you for your efforts as well. (The work you have put into the G-Raider is astonishing!) Doing more research, I found this topic,
including your responses relevant to this issue, and I was not surprised to see that I had already bookmarked it with four stars!

I have concerns, however, about buying a used 100K+ miles engine, in that it might easily develop similar problems shortly after it goes inùa two-day process (IÆm told) for the shop.

If I could get the V6 back (as close as possible) to factory specs with a full rebuild, that would certainly be worth considering. But if I go the rebuild route, and given your advice above, I would have some questions:

- What then are the risks with a rebuilt engine, compared to a replacement engine?
- Might a replacement engine be less or more expensive than a full rebuild?
- Where does one buy the gaskets, etc. for a full rebuild?
- How long might a full rebuild be expected to take?
- etc.

I have not yet found any pages specific to the rebuild process on this Godsend-of-a-forum, and such questions may well be premature until the actual condition of the engine is determined, but it may well be worth considering the choice between the rebuild or replacement so I can start looking for the necessary item(s). It is not unreasonable that such a decision will need to be made at some point, even if I can eliminate the current knocking issue. I must assume that significant work will, at some point (and probably sooner than later), be necessary.

Whatever brief thoughts you would be willing to share at this juncture (I do not enjoy imposing upon others!) regarding rebuild vs. replace would be ôworth their weight in gold.ö

----

mxmikie, regarding the torque converter bolts:
I have looked on this site and wikipedia.com and believe that a torque converter is a component of an automatic transmission; please correct me if I am wrong. I have updated my sig to include ôM/Tö which I believe is understood to mean ômanual transmissionö (which my Raider does have) and I apologize for the omission of relevant data! Thank you again for your efforts!

----

Kevin, thank you for the excellent suggestion to look in the oil (and filter) for metal flakes. I cannot do so here in the wilderness (God Bless satellite modems!! á ;-) á ); I must take Rebecca the Raider into the shop to do so, which then raises the paradox of when to do so:

If I go in soon, I would be greatly relieved to not find any flakes. But if I find the flakes, then I dare not drive back to camp, so I would probably be wise to wait until all possibilities have been ôbrought to light.ö (I REALLY appreciate this forum! and this is also such a wonderful opportunity to yet further my recovery from a severe case of PTSD! á ;-) á )

Blessings and THANK YOU ALL again!,

Richard Fairbanks

Marius, you beat me by a minute! Thank you so much for the link! I will study it in detail tomorrow.

I REALLY appreciate this forum!!

<á.á.á.áoff to stare at the skylight with my eyes closedá.á.á.á>