E46 330ci - Using Excessive Oil.... Any Advice?

[LC23]

I think the test is to have the engine running and remove the oil filler cap. You will hear a change in the engine note and suction from the "hole"

[ftypical]

There are two parts to the CCV: one bit uses vacuum from the inlet manifold to control the pressure in the crankcase; the other bit separates out the oil vapour from the crankcase gases and returns it to the sump.

If the vacuum part fails, you generally get either: oil leaving the engine everywhere as the seals give up under the positive pressure created by having no suction applied, or; the oil vapour gets sucked straight into the inlet manifold due to having too much suction applied.

If the oil separator part fails, no oil goes back to the sump, either because the separator or the pipe work to the sump is blocked.

Assuming that your engine is not leaking oil everywhere, the next thing to check is how much suction is being applied to the crankcase. To do this, take the oil cap off with the engine idling and put a plastic bag over the hole so that it seals. It should be gently pulled inward. If you have to fight to stop the engine sucking it in, it's time to change the CCV.

If all seems well, it's time to check whether the oil is going to the sump or the inlet manifold. The easiest way of doing this is to take the cover off the manifold and unclip the hoses from the CCV to check for oil. If oil drips out, it's new CCV time, unless the problem is a blockage in the pipe work to the sump. Checking this will involve a moderate amount of disassembly and swearing, and will expose the CCV in the process. So you may as well change the CCV while you're there...

[Leeb65]

Thanks, I'll give that a try.

[Argybargy]

I Had the same problem. Switched to 5w-30 and oil consumption has improved.