3.0 Duramax Camshaft Drive Sprocket Replacement

[GmcJing]

2021 Yukon 3.0 Duramax with 30K on it. Check engine light came on so I took it into the dealer to diagnose. Turned out to be the exhaust camshaft drive sprocket had failed.
Anyone else had this problem?
They fixed under warranty but I'm concerned about the cause and possible downstream issues from this failure.

Here are the notes from the repair order:

Camshaft Drive Sprocket Replacement
Effective Date: Nov 1, 2023
LABOR CODE: 4064550
Coverage Code: Emission E, E1
Coverage Code: Powertrain P Includes: To Drain/Fill Cooling System
4WD without F47 LABOR TIME: 27.5
INSPECTED AND VERIFIED CHECK ENGINE LAMP ON WITH OTC P0016
SET IN ECM. REFERRED TO DOCUMENT 5479407 FOR DISGNOSTICS VIA
SCAN TOOL FOUND EXHAUST CAMSHAFT POSITION COUNTER ERRATIC AND NOT WITHIN SIMILAR READING CONDITION OF SIMILAR KNOWN GOOD VEHICLE. UPON DISASSEMBLY FOUND EXHAUST CAMSHAFT DRIVER SPROCKET FAILED.
REPLACED FAILED CAMSHAFT SPROCKET AND CLEARED DTCS. ROAD TESTED VEHICLE AND VERIFIED SCAN TOOL DATA NOW WITHIN ACCEPTABLE RANGE.

 

[DuraYuk]

Sounds like the sprocket failed so the engine was mistimed slightly because of it. No big deal. It isn't common but not unheard of.

 

[OR VietVet]

Keep the paperwork to refer to if happens again. Does not sound like a TSB was involved.

 

[Pro299]

Interesting. Would like to see the failed sprocket. Anyone know if there is a path for broken bits to get to the oil pan?

 

[Silverado4x4]

Sounds like the sprocket failed so the engine was mistimed slightly because of it. No big deal. It isn't common but not unheard of.

A failed sprocket with 30k on it is no big deal? Ummm ok.

 

[randeez]

"CAMSHAFT POSITION COUNTER ERRATIC AND NOT WITHIN SIMILAR READING CONDITION OF SIMILAR KNOWN GOOD VEHICLE"

i doubt it literally failed as in fell apart in the engine.
likely the actuator to control advance/retard was sluggish or leaking and not holding position

 

[StephenPT]

"CAMSHAFT POSITION COUNTER ERRATIC AND NOT WITHIN SIMILAR READING CONDITION OF SIMILAR KNOWN GOOD VEHICLE"

i doubt it literally failed as in fell apart in the engine.
likely the actuator to control advance/retard was sluggish or leaking and not holding position

It's a simple setup w/o variable timing. Exhaust cam has a reluctor ring bolted onto the backside of the sprocket and the camshaft position sensor is installed in the valve cover.

I'd be curious to see if the sprocket actually failed or if the reluctor ring came loose? There was some early QC issues with that reluctor ring. Some of them were bent and if the engine stopped in just the right spot, the cam position sensor wouldn't read it correctly and it would crank without starting.

 

[DuraYuk]

A failed sprocket with 30k on it is no big deal? Ummm ok.

You must understand the design and how it failed. These are simple. And it didn't fail catastrophically.

So yes. shit happens category. That's why you have a warranty. Most issues happen sooner than later if they fail within warranty period.

 

[steiny93]

You must understand the design and how it failed. These are simple. And it didn't fail catastrophically.

So yes. shit happens category. That's why you have a warranty. Most issues happen sooner than later if they fail within warranty period.

I'm pretty sure we all understand the design.
Personally, I consider any necessary engine component failure a quality problem, they shouldn't happen at 30k. This is why the gasser's are getting slammed right now in GM land.

 

[DuraYuk]

I'm pretty sure we all understand the design.
Personally, I consider any necessary engine component failure a quality problem, they shouldn't happen at 30k. This is why the gasser's are getting slammed right now in GM land.

Yeah. It would be nice to live in a world where man made machines had no failure rate.

Guess we can all dream right ?

 

[972sparky]

I watched a youtube of a LM2 teardown after the engine had been replaced due to a failure at around 150K miles. What they found was the cam chains were very loose and the timing of the cams/valves had changed to where the valves were pounding into the top of the pistons, then causing a rod to break in one of the cylinders. Not sure if it had "jumped" some teeth or chain was just too loose. They did not check timing marks during the teardown or if the tensioners were good, all the guides were like new. They also did not measure the chain to see if it was stretched past specs, so could have been any of those problems caused the timing issue. The cam sprockets and the rest of the valve train looked fine though. They did think it may have been caused by chronic low oil level due to some things they found in the lower end but I think that was a symptom, not a cause. On a related note, the dreaded oil pump belt looked like new at 150K, they had to bend it completely back on itself between teeth to see any cracks in it.

To the OP: I would see if they can prove to you that there was no other internal damage due to the exhaust valve timing being off as the valves can hit the top of the pistons. This engine design does not bend valve stems like V engines with canted valves do, so the valve train holds up OK but the pistons take the beating. Just my $.02.

 

[UsualSuspect]

I haven't seen or heard of one failing and we have approx 9 of the 2021's, most have close to, or over 100k. I would think if it were an issue we would hear about it more often. There was a camshaft sensor replaced, but I think that was on the 2019, or 2020's. What I see repair bills for the most are plugged fuel filters, but those are rare. I think we had 1 1500 with a 10 speed have a transmission solenoid act erratically. If there were an issue where we need to schedule downtime to inspect or have it repaired, I would know about that. Most of ours end up out of warranty quickly as they are driven so much. Most of the vehicles we have are from just about any manufacturer due to the shortages a year or so ago, they all have an issue every now and then.

 

[Seamus]

^^^ You have 9 2021 3.0's in service???? If so thats a good barometer?? What oil change interval, and issues are you seeing otherwise?? I look at every carfax i can on higher mileage 3.0's nationwide. No engine work on most everything. Oil changes and filters..thats it.