Need help on 06 Cummins with knock...

[Azhuskcarr]

I just returned home from a camping trip up in the mountains and on the way home I noticed I had a knock coming from the motor. It occured shortly after I pulled a approx 3 mile up hill grade pulling my 5th wheel camper with my Polaris ranger behind it. I was watching my egt's carefully and never let the egt's get over 1250 pre turbo. My rpm's were running close to 3k in 4th gear and my engine temp went up a little but not overheating. I pulled the dipstick and level was fine and checked coolant and everything looked ok. Drove 40 more miles to get home and the truck ran just like it always does with no loss of power or excessive smoke but still had a slight knock that changed with the RPM. I let it sit awhile and then pulled dipstick again to check level to see if I had diesel dumping into my oil pan, but everything looked ok. Took to a diesel shop and we were trying to diagnose the problem when we discovered a pin was sitting in the crack of the G56. Dropped the transmission the next day to find out the clutch let go. So I ordered a SB dd3250 and had the guy install it. Go by today and guess what. That clutch was not the knocking noise. So we checked fuel rail pressure which was ok, then pulled the valve cover and didn't notice anything out of the ordinary. Got tired so I came home. I'am stumped. Do any of you guys have any ideas as to what I need to do to eliminate the obvious things? I hate to have him pull the head and start tearing into the engine. Is it possible that I spun a rod bearing or something??? He is almost positive it's not a fuel delivery issue, but I don't know. I only have 36k on the truck and hate to think that the motor is shot..... Called the dealer and they said my warranty expired last year on the engine and drivetrain... . It's an 06 so I'm expired on the time I guess. Any help would be greatly appreciated and if there are any Cummins techs out there in the Phoenix metro area that could give me some guidance, that would be nice... ... Thanks guys.....

 

[Azhuskcarr]

well got my oil analysis back today. My iron, chrome, and aluminum seem awful high. Tell me what you guys think. They started the leak down test but only have done 1 and 2, so still waiting on that..... #ad

 

[Azhuskcarr]

Anyone in the Phoenix area want to make some side $$$$ and do a rebuild... . Still waiting to see what 4, 5, 6, cylinders come back from the leak down test. The other three were ok i guess. I don't know what to do. Do a rebuild, go buy a reman... and ideas??? First three injectors looked clean with no carbon buildup. I found a youtube video of a guys cummins that had a bad wrist pin and it sounds just like mine does... What the hell, i just turned 36k and I already have problems like this. Very frustrating

 

[HBarlow]

Apparently the shop where you have the truck now is not a competent shop. I would expect a skilled shop to be easily capable of diagnosing the problem.

A loose wrist pin or connecting rod bearing issue could be identified by killing each injector individually. If a cylinder doesn't fire a loose wrist pin or rod bearing won't knock.

A Cummins engine is still nothing more than a man made product containing many individual components also made by humans so it is not necessarily perfect and incapable of failure - BUT - it is very rare for a low mileage, unmolested Cummins engine to suffer an internal failure like you suspect. I've never heard of one failing with such low mileage unless it was modified and abused.

I suggest you take it to a competent Cummins diesel mechanic before you let an amateur begin disassembling the engine.

 

[LNaugle]

I agree with hbarlow... . i would have killed injectors then started capping line til found which cyl then sent that injector out for test and do comp test on that cyl... .

 

[JFought]

the fuel cap is like $30 i already bought it, in preparation

 

[JJPage]

Pull the oil fill cap while running, any excessive blowby? If not, do not get too worried yet.

My 5. 9 gets noisier by the day,these are diesels, they make noise. With your mileage, do not borrow trouble. Run it and keep an eye on fluid levels and fuel consumption, unless something changes drastically, leave it alone, do not let someone tear it apart at this point.

 

[HBarlow]

Another belated thought: What some might describe as a "knock" might be only an injector tick to others. The injectors are often noisy in those engines.

 

[TRAMPLINEMAN]

Would you mind dropping a hint as to which shop you went to?

 

[DonFitzwater]

What's the latest with your engine? My truck had a knock that I recognized as being fuel related (most likely). Replaced my injector and knock is gone.

 

[MStaggs]

I had a very similar experience.

It ended up being a scored #6 piston. #@$%!

 

[JJPage]

I had a very similar experience.

It ended up being a scored #6 piston. #@$%!

OUCH! What was the repair bill on that?

 

[HWestfall]

I had the same sound in my 02 last June scored three cyl. and two pistons got replaced. $4,000 H Westfall



02 3500 HO

 

[JJPage]

I had a very similar experience.

It ended up being a scored #6 piston. #@$%!

I had the same sound in my 02 last June scored three cyl. and two pistons got replaced. $4,000 H Westfall



02 3500 HO

What was the cause? poor fuel? faulty injector(s)?

 

[HBarlow]

Magic black boxes.

 

[CKelley1]

harvey i like your answer, it would have taken me 50 words to not say it as clear.

 

[HBarlow]

Thank you my friend. Unfortunately my three word comment will anger a few.

 

[MStaggs]

OUCH! What was the repair bill on that?

$12k when all was said and done. :{

 

[Prairie Dog]

Once when towing up a mountain pass and pushing it real hard, I had a knock that could be felt through the whole truck. After going over the top the knock slowly diminished and never came back. This was 2 years ago.
Hope you have the same luck.

 

[LNaugle]

Harvey... . You make me laugh... !