2016 BMW X5, N57 tri-turbo, 150k km, Fuchs GT1 5W30 12k km OCI

[more_fasterer]

Here's the third UoA, with a change interval of 4,000km to match up to the previous UoA as much as possible. Iron is still high, plus PQI and Aluminium are both up, which is a bit of a concern. The oil filter had a couple of small flakes of metal in it but nothing worrying or abnormal.

The diesel dilution is consistent with the previous oil change, but interestingly this time around all of the dilution happened in the first half of the oil change interval - the oil level hasn't increased at all in the last 2,000km. This is the inverse of what happened in the previous OCI.

I'll keep the next OCI at 4,000km to see if there's any improvement.

 

[fantastic]

Don't remember but did you happen to run some high strength ratio fuel injector cleaner? What is Enviro? Get some fuel injection cleaner through those injectors. Otherwise it may be that you'd want to send them off for cleaning/inspection to rule them out. 5w-50 or 15w-50 grade in the meantime with that high level of fuel dilution. That just plain sucks & I don't like to hear of a nice car having so much fuel troubles. Hope you figure this out. That high fuel is contributing to your high wear numbers and does appear to be mainly Fe wear.

 

[more_fasterer]

Yeah I ran some strong fuel system cleaner through it back in March; immediately after that the last bout of diesel contamination started happening. The injectors were tested and came back as not leaking and with reasonable atomisation.

If the oil level starts to rise again I'll get a leakdown test done.

Here's the spec sheet for Penrite Enviro+: https://penriteoil.com.au/assets/pis_pdfs/ENVIRO+ 5W-40 (FULL SYN.).pdf

 

[twX]

The low phosphorus on these UOAs is curious. The spec sheet claims 770 ppm, but it's ended up much lower on every OCI.

I wouldn't rule out testing error, but phosphorus loss is known to happen, and it's been low for 3 UOAs now. API SP oils require 79% phosphorus retention after a 90-hour test at high load with extremely hot oil. Your oil is down to 76% phosphorus at 4,000 km even after accounting for the effects of fuel dilution, which is pretty unusual.

You might try switching to a different brand of oil. The one you're using might not have a very stable form of ZDDP. I kind of doubt your wear is related to ZDDP getting too low on these short OCIs, but if the oil is actually losing phosphorus, it's going into the DPF which won't be good for it. I'd also consider a 10W-40 to help deal with the low viscosity from the fuel.

I wouldn't be too worried about a PQI at this point, so long as it doesn't keep increasing.

 

[more_fasterer]

Yeah I wonder if you might be right about the testing error, seeing as the first UoA was for a Fuchs oil instead of Penrite. I can't find the datasheet for the Fuchs oil so I don't know if was meant to have a similar Phosphorous count, but it's also an API SP oil

Thanks for the advice guys!

 

[more_fasterer]

Here's the 4th UOA. I'm still chasing the source of the fuel dilution, but hey, at least the iron count is going down.

I managed to time the OCI wrong and ended up doing 5,000km on this oil.

This fill I've switched to Liqui Moly Top Tec 4100 5W40. Heavier viscosity oils that are LL04 compatible don't seem to exist, unfortunately.

 

[mattd]

Does this engine utilize in cylinder dosing for DPF regeneration? Not familiar with this particular engine.

 

[more_fasterer]

Yes it does - it fires the injector on the exhaust stroke