Hi guys, my mum just passed me her bmw e60 lci with a n52k engine (black cover) 1 year ago, and I have done 2 oil changes with ENOC full-syn oil 5w-30 with an OCI of 10k KM (roughly 6 months). The car has not been used much for the past 2 years before i started using the car.
Then on last week to my regular mechanic to fix a leaky VCG, saw this after the workshop pulled out the valve cover...
A few options came into mind:
1. Shorten OCI (to 5000 km) with good quality full-syn oil, no engine flush, pray for the best
2. Shorten OCI (to 2000 km) with HDEO (Rimula R6 or similar), repeat a few OCI and hope to clear out most of the sludge
3. Engine Flush right before my nxt oil change (liqui moly pro line engine flush) with cheap fresh lube after drain out the used oil, let idle for 10 mins, drain again, and refill with good lube.
4. Slow engine flush with short OCI (3000 km), like instead of doing a full engine flush to the recommended concentration (700ml for 7 quarts of engine oil), i will put in 100ml of liqui moly engine flush and let idle for 10 mins before drain and refill with good oil. Repeat until all sludge is gone...?
Please advice as i am planning to keep the car around for a few more years, and really do not wish to spend tons of cash for engine overhaul if the situation worsen.
Picture speaks a thousand words...
View attachment 40145View attachment 40146