BMW X3 xDrive28i N20,146k, 7.5k M1 Euro OW40 , high wear

[levesqu6]

Not sure what to make of the wear metals but from looking around the forum this is not normal for this engine. At 12.8 iron per 1kmile this is just under the 14.1 i saw for someone breaking in a n20 after a engine replacement.

I spent sometime tonight looking at the intake path and filter. Filter is a Hingst (OEM) and the box filter, and intake path all look to be in good shape except the pipe that brings the PCV to the turbo inlet pipe. It was only clipped on one of two sides and is all oily in the area. It didnt look dirty inside the tubes and it doesnt seem like it would have been leaking much air but it certainly was leaking some. No codes for MAF air flow being unbalanced or anything like that. The inlet pipe to the turbo has some oil residue on it but i think that is coming from elsewhere.

I havent been in this engine since 127k to do the vacuum pump and I did the turbo at 119k because of the wastegate.

This engine is one of the vintages with the infamous timing chain issue. It does not appear to have ever been replaced on this vehicle. There is no evidence that it is a current problem either. Since the chain is essentially wrapped in plastic guides, something related to it wouldnt show up as high aluminum too.

Oil filter looked great when i looked in the pleats. Mann filter used. Oil change before this would have been castrol 5w40

 

[edyvw]

That is a lot of iron.
My understanding is that it is timing chain guides that is an issue, not chain itself.

 

[levesqu6]

I did a fair amount of research on the timing chain. Read some court docs from the class action lawsuit. My take on it is a combination of factors but the failure is do to elongation of the chain from wear that eventually exceeds what the tensioner can take up. Then the chain slaps the guides and breaks them.

BMWs proceedure for chain replacements supports this idea. They measure chain elongation with ISTA or with a tool that goes into the spot the chain tensioner goes. They use a microphone or accelerometer to check the lower chain that runs the oil pump. Ive read that it whines before it lets go.

The chain and upper guide are shared with the n52.

In 2015 they revised the part no for the timing chain, the tensioner and the oil pump chain. No changes to the guides. if you put the tensioners side by side the newer one has more stroke.

why this doesnt happen in the n52 probably has to do with the N20 being DI, lower oil capacity, and maybe the geometry of the tensioner is different in the n52 so it can take up more slack. Both engines had crazy long oil change intervals. which we saw get revised down in the era of the n20.

thoughts on why the iron is high? air filtration issue?

 

[Jetronic]

the silicon doesn't seem abnormally high, but the particle sizes that can be seen by gas chromatography are small, the bigger and more damaging particles can't be seen. However, if that was the cause, there should be bearing materials in the oil aswell.

I think you have another issue, like a broken or stuck piston ring. maybe do a compression and leak down test, or have a look with a borescope.

 

[KEVINK0000]

Do the chain update and see iron drop to normal levels.We have one of these engines in the family, and I spent a fair amount of time looking into this issue, as you did. I did not have the pleasure of having to do this job, as it was done by dealer right before our purchase. If this was mine, I would begin working on it asap. The chain is likely oscillating enough to begin high wear, and the next stage is broken guides.

 

[fantastic]

High metals obviously & I have no idea about the details of this engine. I hope you can figure it out.

 

[buster]

the silicon doesn't seem abnormally high, but the particle sizes that can be seen by gas chromatography are small, the bigger and more damaging particles can't be seen. However, if that was the cause, there should be bearing materials in the oil aswell.

I think you have another issue, like a broken or stuck piston ring. maybe do a compression and leak down test, or have a look with a borescope.

Right. This is the tricky part. You have people saying UOA's don't matter and can't be used to show actual wear (it is wear), but then you see wear elevated. Particle size is the issue as you stated. UOA's can only see up to a certain size.

 

[levesqu6]

engine is a turbo DI turbo 4 2.0L. Aluminum block (AlSi9Cu3) and electric arc spraying process to coat the bores. The tech manual says the material they spray into the bores is a thin layer of iron.


Stuck ring
I see some posts suggesting that we'd likely see elevated chrome from the ring(s) if there was a stuck ring?

For what its worth, oil consumption is very low on this engine. No top off over the 7.5k interval here though it was getting close as i removed just over 4quarts of the 5 i put in. I cannot confirm it for this engine but the n55 of this era had a ceramic chrome coating on the rings. This engine shares various bits with the n55.

Does no elevated chrome and sane oil consumption suggest that a stuck ring is unlikely?

Timing Chain
really interesting idea that there could be extra wear from the chain/sprockets from it moving about more from it reaching the limit of what the tensioner can control. I dont think it explains the elevated aluminum though. Just not sure where the aluminum would be coming from. The chain is basically wrapped in plastic (see pic) and i would expect everything related is some sort of steel. I had an idea that the aluminum could be from the tensioner itself oscillating but again thats clearly made of steel.

Timing chain is a non trivial expense and job so would want to make sure before diving in. Obviously a complete engine is an ordeal too if it goes completely sideways. It's unclear how prevelant this issue is. I ran the ISTA test last night and this version of the ECU isnt able to do the test. Perhaps i'll by the elongation testing tool.

Its just Dirt in the intake
I did find that not fully seated PCV hose at the inlet to the turbo...

Bearings in this engine are lead free. Digging these are G-488 and G-444 material which is a lead-free copper substrate with silicon and nickel, and an inter-metallic tin-nickel. These are tin-nickle top layer, then bronze intermediate layer, steel backer. Haha of course we see no nickle or tin in this analysis but we do see a regular amount of copper. Journal of the turbo bearing is likely bronze.

Perhaps dirt ingestion through the air intake would just cause wear in the bore (iron and al) and not make it to the bearings since those are post oil filter? Then again the piston rings do have a chrome coating and we do not see it...perhaps that coating is long gone.

 

[edyvw]

I did a fair amount of research on the timing chain. Read some court docs from the class action lawsuit. My take on it is a combination of factors but the failure is do to elongation of the chain from wear that eventually exceeds what the tensioner can take up. Then the chain slaps the guides and breaks them.

BMWs proceedure for chain replacements supports this idea. They measure chain elongation with ISTA or with a tool that goes into the spot the chain tensioner goes. They use a microphone or accelerometer to check the lower chain that runs the oil pump. Ive read that it whines before it lets go.

The chain and upper guide are shared with the n52.

In 2015 they revised the part no for the timing chain, the tensioner and the oil pump chain. No changes to the guides. if you put the tensioners side by side the newer one has more stroke.

why this doesnt happen in the n52 probably has to do with the N20 being DI, lower oil capacity, and maybe the geometry of the tensioner is different in the n52 so it can take up more slack. Both engines had crazy long oil change intervals. which we saw get revised down in the era of the n20.

thoughts on why the iron is high? air filtration issue?

The OCI is not crazy, it is 10k. That is actually lower than in EU. However, I personally would stick to 5k OCI (might help delay issue, but I think in your case it is done deal).
I would echo what others said. Change chain and parts and be done with it. Why on N20 and N52? Various reasons but those are also far different engines. One has very linear torque, another has rapidly developing and more torque, among other things. Also, in N20, I would stick strictly to XW40 oils that are LL01 approved (since 2018 all LL approvals have N20 chain test).

 

[levesqu6]

The n20 was originally released with 15k intervals. 10k came with 2014 model year. I recoded this car from 15k to 7500. When they revised to 10k, they did not recode cars at the dealer as they saw them.

I'll likely order the elogation measurement tool to see where its at. It's a non trivial expense and time investment to do without being certain. probably take me a whole weekend to do the job, $800 in parts, few hundred in tools. paying a shop is getting into buy a n55 parts car territory...

 

[fantastic]

engine is a turbo DI turbo 4 2.0L. Aluminum block (AlSi9Cu3) and electric arc spraying process to coat the bores. The tech manual says the material they spray into the bores is a thin layer of iron.


Stuck ring
I see some posts suggesting that we'd likely see elevated chrome from the ring(s) if there was a stuck ring?

For what its worth, oil consumption is very low on this engine. No top off over the 7.5k interval here though it was getting close as i removed just over 4quarts of the 5 i put in. I cannot confirm it for this engine but the n55 of this era had a ceramic chrome coating on the rings. This engine shares various bits with the n55.

Does no elevated chrome and sane oil consumption suggest that a stuck ring is unlikely?

Agreed

Timing Chain
really interesting idea that there could be extra wear from the chain/sprockets from it moving about more from it reaching the limit of what the tensioner can control. I dont think it explains the elevated aluminum though. Just not sure where the aluminum would be coming from. The chain is basically wrapped in plastic (see pic) and i would expect everything related is some sort of steel. I had an idea that the aluminum could be from the tensioner itself oscillating but again thats clearly made of steel.

I was thinking the same thing. Is there any aluminum nearby the chain that the chain could be scraping against?

Its just Dirt in the intake
I did find that not fully seated PCV hose at the inlet to the turbo...

Bearings in this engine are lead free. Digging these are G-488 and G-444 material which is a lead-free copper substrate with silicon and nickel, and an inter-metallic tin-nickel. These are tin-nickle top layer, then bronze intermediate layer, steel backer. Haha of course we see no nickle or tin in this analysis but we do see a regular amount of copper. Journal of the turbo bearing is likely bronze.

I think the Europeans moved towards Pb free bearings before the US. I think some bearings use aluminum as well but no idea on your engine. Sorry no help.

 

[sfbmw]

he n20 was originally released with 15k intervals. 10k came with 2014 model year. I recoded this car from 15k to 7500. When they revised to 10k, they did not recode cars at the dealer as they saw them.

I'm interested to know how you were able to recode the OCI interval in the CBS? I wasn't able to find anyway to change that via FDL coding through Esys last I looked.

 

[levesqu6]

The interval is in the CBS and DME. Unfortunately it does not change right after. I recall coding it and it not changing and then eventually one day i noticed that it changed. I think there was a reset of the oil change in there too. I followed this guide.

here are the available codings. This car was 8KB and i moved it to 8KM. looks like you can go down to 5000mile with 8KP

 

[edyvw]

The n20 was originally released with 15k intervals. 10k came with 2014 model year. I recoded this car from 15k to 7500. When they revised to 10k, they did not recode cars at the dealer as they saw them.

I'll likely order the elogation measurement tool to see where its at. It's a non trivial expense and time investment to do without being certain. probably take me a whole weekend to do the job, $800 in parts, few hundred in tools. paying a shop is getting into buy a n55 parts car territory...

15k miles is EU standard (EU was in some countries 25k km). But, going to 10k is more related to sulfur issue back then in the US gas.
I really did not venture into looking timing chain issues in N20, but can't you see timing and see if it is off. On VW EA888 that has elongation issues, I can actually see cam bank phasing and usually about 4.5 degrees you are entering territory of "start thinking of timing chain job," while above 5.5 you are on borrowed time. I was wondering if you could see that using ProTool or similar software.

 

[Jetronic]

I was thinking the same thing. Is there any aluminum nearby the chain that the chain could be scraping against?

I have never had a timing chain hitting aluminum parts, without making a lot of extra noise. It should be obvious.

 

[KEVINK0000]

No, it doesn’t have to be loud to be taking place. Depends on where it’s touching. The iron is a telltale especially on this engine and mileage, in my opinion. The aluminum also indicates investigation is warranted.

 

[levesqu6]

I dont see how the chain could be reahing out to touch alumnum anywhere without the guides being basically destroyed.

I inspected the timing guide with a bore scope last night and found no issues. There are common places i have seen people find cracks in the guides before they come completely apart and those areas were fine. I did a quick smoke test on the intake to the turbo and didnt find any leaks. I tried to reproduce the unseated PCV hose to see how much smoke i got out and wasnt able to get anything out. Might be because ive since cleaned it up and the oring is now in a new position. It was pretty flat on parts of the oring when i pulled it. Im going to replace that hose since one of the clips broke.

I think the next reasonable thing i could attempt to do is get a timing chain elongation measurement tool and see what that tells me. Then just seeing what the oil looks like at 5k miles. wife drives this thing a ton, that wont be that long from now. She put 1200 miles on it before the blackstone results came back.

 

[Nathan]

Low flashpoint indicates fuel contamination.
Fuel will wear piston skirts and bores aka aluminum and iron.
Run a good injector cleaner a couple times like Redline SI-1

 

[edyvw]

Low flashpoint indicates fuel contamination.
Fuel will wear piston skirts and bores aka aluminum and iron.
Run a good injector cleaner a couple times like Redline SI-1

Blackstone is not that accurate with % of fuel. Also, was sample taken cold or hot is important.

 

[Nathan]

Blackstone is not that accurate with % of fuel. Also, was sample taken cold or hot is impotent

Good point about sample conditions.
Maybe I'm totally out to lunch and aluminum and iron have nothing to do with fuel contamination.