Where is my oil going?

[elbekko]

Bosch 4.6 P38, 295k km. It recently started using more and more oil, and it's getting ridiculous now. Did an oil change less than 1000km (around 2 weeks) ago, and had to refill 2-3 L today

There's no smoking on startup or under load, and the engine doesn't seem to be leaking (can't be 100% sure as the front diff is spewing oil around, but fixed that today).

If it's using that much oil, surely it should be smoking like mad?

[Bowie69]

Get some one to follow you and boot it a few times when really hot, at that mileage it could well be burning quite a bit... but hard to see yourself.

[Tanuki]

Catalytic-converter-equipped vehicles don't usually show the classic worn-engine sign of blue oil smoke in the exhaust unless they are burning oil at a rate of a supertanker-full every few Km.

The catalytic converter quietly oxidises away the oil-smoke and the exhaust gases remain invisible.

I'd suggest a compression test as the first stage, along with close examination of the spark-plugs while they're out. Look for any 'crusty' deposits or obvious signs of oil on the electrodes.

[elbekko]

Hmm, fair point about that cat. That does explain.

The plugs did indeed not look too good, not oily as such but indeed a few deposits. I did do a compression test then, but only on one cylinder (pretty worthless), but that was perfect.

I also had a friend put his hand over the oil filler, and he couldn't feel any blowing, but that was with a cold engine.

I guess it's compression test time then