Hi Everyone,

New to the Cayenne and Prosche community here, long-time BMW owner, recently got a 2014 Cayenne S (4.8 NA), 120K KM, overall pretty good condition.

Oil was due for a change before i picked it, and oil level went from full to empty in a few hundred kms. Added some Liqui Moly engine flush before oil change, drained and refilled with 9L Shell 5W40 (A40 certified), oil level was at 3/4 after a short drive, and it went down another 1/4 in less than 100km.

It does not smoke during normal running nor on cold start, borecoped a single cylinder and there is visible wear (small shiny patch, does not look to have depth) but nothing near to actual scoring.

Haven't had a chance to check compression yet, but it runs pretty smooth with no notable misfires on idle and under load, revving it on neutral feels a bit funny (seems to vibrate a little excessively but does not feel like a misfire, and i don't have an accurate frame of reference).

My first suspect was AOS, the oil cap vaccum felt quite high, I don't have a guage so this is very rough comparison: on my BMW N52 (NA L6), the vaccuum is very slight, and on the Cayenne it requires notable grip to open the cap with the engine running. If opening the cap on the N52 is like picking up a wallet, then on the Cayenne it's like picking up a 500ml bottle of water. This is the same after replacing the AOS, not sure if there are other parts involved in the PCV system?

What bugs me is with such a high consumption, there is not sign of running issues nor smokes, and how the crankcasse vacuum is still rather high with new AOS.

Thanks in advance for any help.

 

Crankcase vacuum is high on these so what you are experiencing with oil cap is considered normal. Your oil level indicator is 250mls per notch so ~1ltr on the gauge. I suspect you have under-filled and the gauge may have been on the cusp of two bars. Try performing a service reset and check via a scan tool for the actual oil level which may be more accurate. They do burn oil and Porsche say up to 1ltr per 1000klms is acceptable but I would be concerned at that consumption especially at the K’s. If you find it is burning more than a couple hundred mills per 1000ks i would switch to 5/50 weight and see if it improves, also perform a comp test.

https://rennlist.com/forums/cayenne-...ata-point.html

 

Hi Tim,

Thanks for the info about crankcase vacuum, now i have one less thing to think about.

I actually did read the post you referred to before i changed oil, 9qt is ~8.5L so that person actually had 8.75L in total after top up. For that reason, I filled mine with exactly 9L, but some local sources does say 9.5L.

Anyways, I am looking for a porsche specific diagnostic tool as i only have BMW ISTA at this time.

Yes, a comp test is planned, will report back on that. But if that comes back good or slightly below spec, I guess it's safe to presume it's sticking piston rings? Given the relatively low mileage, I am thinking valve stem seals are less likely or at least do not contribute to the oil consumption as much.

 

Regarding the oil filler cap qualitative test you performed. I would recommend you build a tester by spending a few dollars on an hvac manometer and an oil filler cap to modify with a nipple. This will deliver a quantitative answer before you spend resources on guesstesting.

 

A compression test wont tell you much if its the oil scraper rings , Will be interesting to see what it comes back as . Sounds like scoring or oil scraper rings are buggered.

Car pretty well takes a full 10 litres with filter.
I have a 2013 with similar mikage 127k km.

still shows full after about 4K km since last oil change.