940 smoking/burning oil

[Jelle9990]

My 940 B230FT has started to smoke between gears and when I’m pushing the clutch in coming to a stop, it doesn’t seem to smoke under load at least not very noticeable...
It did it one day and smoked like crazy almost all the time. I checked through the forums and thought it was maybe the turbo going bad or the pcv system. Pulled the pcv system apart and it was totally clogged... cleaned everything and put it back on and it was WAY better but now its like I described at the top^
It’s a big cloud of whiteish smoke(as far as I can tell) and has a strong scent of burned oil..
I don’t know if it matters but I installed a catch can a while ago and it filled “okay” fast, I gave it some engine cleaner(10min idle), new filter, new oil(cheap semi 10w40) and some liqui moly motor oil saver. Drove it granny style for 900km and changed filter and expensive oil(fully SYN 10w40) and know it developed this problem after awhile and there is close to nothing in the catch can even after cleaning the pcv system..

Best regards Jesper

[bob12]

I don't know much about these things but, I always though that fully synthetic oil was not advisable for these older engines. Bob

[griston64]

I've always used semi syn in mine. 10w 40

[griston64]

Have you overfilled with oil ??

[Rversteeg]

My B230FK is on fully synthetic Shell Helix Ultra 5W40 for many years now and seems to like it. And it keeps the engine clean (left picture is mine obviously). Even after 400K miles I never have to add oil between service intervals and never had to clean the PCV system.
Smoke on gear changes or deceleration is caused by high vacuum in the intake. (worn valve stem seals?). If the turbo is the problem you will probably also find a lot of oil in the air intake hoses between turbo and engine. If the oil loss is on the intake side of the engine you would also expect the spark plugs to be black.
Is the burning oil you smell not simply caused by working on the engine and touchiung the exhaust with greasy hands?

[Jelle9990]

Originally Posted by griston64

Have you overfilled with oil ??

Nope its not overfilled it’s still smokes at minimum oil level..
A lot of people suggested fully synthetic oil so that’s what I went with.

[Jelle9990]

Originally Posted by Rversteeg

My B230FK is on fully synthetic Shell Helix Ultra 5W40 for many years now and seems to like it. And it keeps the engine clean (left picture is mine obviously). Even after 400K miles I never have to add oil between service intervals and never had to clean the PCV system.
Smoke on gear changes or deceleration is caused by high vacuum in the intake. (worn valve stem seals?). If the turbo is the problem you will probably also find a lot of oil in the air intake hoses between turbo and engine. If the oil loss is on the intake side of the engine you would also expect the spark plugs to be black.
Is the burning oil you smell not simply caused by working on the engine and touchiung the exhaust with greasy hands?

That looks pretty clean! I haven’t opened up my engine(yet) but if I look through the oil cap hole it looks pretty spotless. I’m gonna try and take the plugs out and see if they are black and I will return with an update!
No it’s not from my greasy hands but I’m pretty sure from the big cloud of smoke coming out my exhaust

[Jelle9990]

Here is the plugs! Don’t know why it doesn’t wanna upload the picture from cylinder 3, but I looks like the others soo I guess it doesn’t matter too much

[Laird Scooby]

You may have already fixed the problem but the intercooler might be full of oil - worth checking! Could still be the turbo oil seals.

The redblock was never designed for fully-synth, the molecules are too small so it's not advisable to use it. I'd suggest a 15W40 semi-synth good quality (not stuipdly expensive quality but reasonable) and cleaning the PCV system again and also the intercooler.

[griston64]

Hi Dave

Service book for UK suggests 10w 40 semi which is what I've always used.And also just bought to do a change next week. Is 15w 40 better for the engine ? Or an older engine ?

Cheers, Mark