[Billfitz]

The problem may be the guide. We know that when a chain goes that the guide goes, usually the oil pump and pump chain go, and lots of other stuff as well. Which goes first, the guide or the chain, is still being debated. Did the chain stretch, causing the guide to break? Or did the guide break, causing the chain to come off the sprockets and break? We know that the chain design was changed as of 01/01/2015. Rumor has it that the guide was also changed, but the part number has not. That rumor has been bolstered by pictures of a used guide being a brown color, while a new guide is white, but that's only because the guides are stained brown by the engine oil over time. And then there's the tensioner. That part was changed 08/15/2016. Some have advocated changing the tensioner at 30k miles as a preventive measure. There's lots of anecdotal evidence, but what we know is still a lot less than what we don't.

[mikessc]

Originally Posted by Billfitz

The problem may be the guide. We know that when a chain goes that the guide goes, usually the oil pump and pump chain go, and lots of other stuff as well. Which goes first, the guide or the chain, is still being debated. Did the chain stretch, causing the guide to break? Or did the guide break, causing the chain to come off the sprockets and break? We know that the chain design was changed as of 01/01/2015. Rumor has it that the guide was also changed, but the part number has not. That rumor has been bolstered by pictures of a used guide being a brown color, while a new guide is white, but that's only because the guides are stained brown by the engine oil over time. And then there's the tensioner. That part was changed 08/15/2016. Some have advocated changing the tensioner at 30k miles as a preventive measure. There's lots of anecdotal evidence, but what we know is still a lot less than what we don't.

Read post #63.
That is my car and it is in the workshop now with the VC off.
The chain did not stretch and there is no whining noise.
But the part where the side guilde rail clip on to top rail is broken.
IMHO nothing will stop this and whether BMW change the guide or not is immaterial. IMHO this will happen again after 50 or 60K miles.

My workshop see alot of N20 with this problem with mileage around 60K miles. In my country, 95% of BMW F series car are with N20 engines as 6 cylinders car are super expensive here.

IMHO BMW is anticipating more cars will have this problem. That's the reason why they widen the US tiiming chain 7/70K extended warranty to include cars that produced up to Feb-2015.

[Billfitz]

Since your chain has not broken that part of the guide which is broken can't be blamed for chain failure. There's no way to know if the far more catastrophic damage seen with guides where the chain has broken was caused by the chain breaking, or if the guide broke first and then the chain. My money is on the chain being at fault, and apparently so is BMW's, since they changed the chain, but not the guide. At any rate, if the potential for timing chain failure after 60k miles is worrisome, sell the car at 50k miles.

[F30ed]

Originally Posted by mikessc

Clearly a flawed design.
The problem is the guide rail.
Look carefully and you will see crack where the side rail clip on to the top rail.

Car does not have any whining noise at all.

Fantastic evidence, thank you very much.
1) Broken plastic connector apparently is not a problem. It has no load any way, and if it does not block anything when falling down, there is pretty much no harm done (nothing broke not even whining noise)

I guess the defect is in the chain itself. It is made of material that in some cases can stretch, deform, elongate and as the result cause dreadful whining noise, destruction of the plastic rail, failure on the oil pump. ( I posted pictures of elongated chain a couple of years ago). Plastic might be just the victim, it falls apart under vibration and striking force of elongated chain.

[mikessc]

Does not matter whether guide is broken or chain is stretch.

Ultimate they will result in catastrophic failure.

I think we should agree that the problem eixsts and it is REAL.

[mikessc]

Originally Posted by Billfitz

Since your chain has not broken that part of the guide which is broken can't be blamed for chain failure. There's no way to know if the far more catastrophic damage seen with guides where the chain has broken was caused by the chain breaking, or if the guide broke first and then the chain. My money is on the chain being at fault, and apparently so is BMW's, since they changed the chain, but not the guide. At any rate, if the potential for timing chain failure after 60k miles is worrisome, sell the car at 50k miles.

BMW bulletin actually indicate to replace the guide.

https://bmwtechnician.com/2017/08/02...-bmw-bulletin/

[mikessc]

Originally Posted by F30ed

Fantastic evidence, thank you very much.
1) Broken plastic connector apparently is not a problem. It has no load any way, and if it does not block anything when falling down, there is pretty much no harm done (nothing broke not even whining noise)

I guess the defect is in the chain itself. It is made of material that in some cases can stretch, deform, elongate and as the result cause dreadful whining noise, destruction of the plastic rail, failure on the oil pump. ( I posted pictures of elongated chain a couple of years ago). Plastic might be just the victim, it falls apart under vibration and striking force of elongated chain.

The broken plastic will drop into the oil pan and suck up by the oil pump to the oil tube which has a metal screen in it.

This will block oil supply to the engine and cause low oil pressure.

This is the reason why most people encountered 'Drive Drain malfunction'
, 'Oil pressure low' fault when catastrophic failure happen.

The low oil pressure will cause lots of things to fail.

Few pieces of the plastics are alraedy in my oil pan now. LOL.

[kobluna]

Originally Posted by mikessc

The broken plastic will drop into the oil pan and suck up by the oil pump to the oil tube which has a metal screen in it.

This will block oil supply to the engine and cause low oil pressure.

This is the reason why most people encountered 'Drive Drain malfunction'
, 'Oil pressure low' fault when catastrophic failure happen.

The low oil pressure will cause lots of things to fail.

Few pieces of the plastics are alraedy in my oil pan now. LOL.

Interesting what you found there. Makes me wonder if it would be easier to investigate oil sump for pieces of plastic or to remove valve cover to investigate guides themself, if the only reason of the job is to check if guides are broken or not. For you it obviously made sense to remove VC as you needed to replace the gasket anyway.

If the guides brokes because of vibration it might make sense to use higher rpms than what automatic does when driving D/eco or comfort. So either put in S/comfort or D/Sport. At least I can feel the engine vibrating in certain speeds (i.e. 55kmh needle speed) with D/Comfort and rpms in the range of 1100-1300.

[mikessc]

Originally Posted by kobluna

Interesting what you found there. Makes me wonder if it would be easier to investigate oil sump for pieces of plastic or to remove valve cover to investigate guides themself, if the only reason of the job is to check if guides are broken or not. For you it obviously made sense to remove VC as you needed to replace the gasket anyway.

If the guides brokes because of vibration it might make sense to use higher rpms than what automatic does when driving D/eco or comfort. So either put in S/comfort or D/Sport. At least I can feel the engine vibrating in certain speeds (i.e. 55kmh needle speed) with D/Comfort and rpms in the range of 1100-1300.

Easier to remove valve cover.
BIG JOB to remove oil pan as you need to drop the subframe.

[adumesny]

older thread... I wanted to be pro-active before it becomes an issue.

528i N20 11/2013 production with 70.8k miles so slightly past the 7y/70k warranty on mileage side. I don't hear any whinny noise (from other videos), and looking at chain from oil filler I don't see any chain wear either. Is there anything else I can relatively easily check before my warranty runs out (9 month but already past in mileage).

I see #63 post about removing valve cover - but with no chain noise - how hard is that ?

[pierreye]

At that mileage, even if you don't have the timing chain issue, it's almost time to change the engine gasket. I would ask them to check during gasket replacement.