STP Engine oil flush

[Speedtouch]

Just acquired a 1997 E39 523i with the M52B25 engine, with around 154,000 miles on the clock, and rather black looking engine oil with some slight 'mayonnaise' under the oil filler cap - so an engine oil & filter change is obviously required.

Engine otherwise starts easily and sounds good.

Is it advisable to use STP Engine flush to clean out some of the gunk, or is this a no-no on the M52 engine?

[ross_jsy]

I don't like using those types of additives. I would recommend doing an oil and filter and use diesel oil, and change it in 1000 miles or so

[DanThe]

No need, just use fully synthetic oil and change it more frequent, using the engine 'properly' will soon move some of the muck rather than tickling the throttle for a couple of miles per day and barely getting it up to temp

[reggid]

use a cheap oil drive around block and drain it then fill with oil and filter of choice