Hi All, My 01 330Ci has just turned 108,000 (ordered it new). Should I consider having the air/oil seperator and associated hoses replaced? I am thinking it may be good preventive maintenance as I plan to hold on to this car for a long time. Sean
It is not a bad idea to repace that stuff. It does go bad. While you are at it, replace the intake boot(s).
No need to PM me, this is all posted to help everyone. Anyhow, if you go to the dealer, they will know what you are talking about. I will always recommend a knowledgible independent BMW shop over the dealer though. Ask around your home town to find one. You will save money, and you will get better service if you find the right shop.
My 99 328 has quit a fe miles. 164k so I always wonder about this oil/seperator thing, as it looks like a pita to change. So my questions are, what happens when it goes bad, What are the syptoms, what makes them go prematurely?
Symptoms of a bad separator: Poor idle hissing noise under hood from vacuum leak Check engine light Excess oil consumption (it can cause excess crankcase vacuum and suck in too much oil) Sometimes they crack, sometimes the hoses rot off it, sometimes it stops limiting vacuum the way it was designed to. If you are clever, it should take only a few hours. If you have done it before, you might get lucky and do it in an hour. I believe that some manuals I have seen call for you to pull the intake, but I never have.
I've heard you can test your cyclone separator by pulling the dip stick and watching for a large change in idle or even the engine dieing. Is this true?
It might be true because on a car without these things, doing that would pull in unmetered air, whereas a functioning cyclone separator is also a vacuum limiter to prevent the intake pulling too much vacuum on the crankcase. Probably to prevent burning too much oil. Sounds reasonable to me, so much so that next time I am around one of these cars, I'll try it.
I changed the oil separator on my '01 325iT without removing the intake manifold but I did unbolt the engine wiring harness distribution block from below the intake and I removed the throttle body (you will obviously need to remove the MAF/boots and the air-filter assembly). This gave some more room to get at the actual separator and to get at the line that runs from the dipstick tube to the separator. It is tight quarters to get at all of the parts but a little patience goes a long way. Note that there is an SIB out there for cars with the M54 engine used in cold climates. It recommends to install updated hoses and separator along with an updated dipstick guide tube. The SIB number is 11 08 03 and is dated 10/2007. Matt
