Subject: Re: oil separator ruined engine???? Author: renny : member since February, 2009 : 2 posts Posted on: 2009-02-03 22:47:58

I'm coming into this a bit late (by about a year), but it will be an ongoing issue with BMWs, not just E46. A friend runs a BMW repair shop and he tells me that any BMW with a seperator in it can have this problem.
First off, if missed, yes it can toast the motor. When the seperator freezes up the crankcase goes into a pressureized state and blows the oil out where ever it can. That can be by the rings, valve stem oil seals, valve cover gasket, pan gasket and even up the dipstick.
When the seperator first freezes up, the engine will start to smoke heaily if the oil is going into the combustion chamber or into the exhaust, but often very little goes there and in winter it is difficult to tell if there is any extra exhast. If the frozen condition continues, oil will continue to be dumped where ever. Most of the time the only warning you might get is a low oil level light. Add to that the system very seldom tosses a defect code, even when oil is running out the tail pipe or coming out the intake manifold.
BMW Canada is aware of this cold weather issue, but there is no bulletin or repair procedure listed and if we don't you can bet the USA and others don't either.
He has found two things that seem to work to prevent this issue. One is to let the car warm up on the driveway for about ten minutes so that the oil and other parts are warm. This seems to get enough heat into the system that the water evaporates rather than condenses and freezes when the motor is shut off. In addition, he recomends that the car be run for about a half hour each time it is started to keep condensation from building up in the seperator.
The second more drastic solution was to disconect the line, plug the seperator end and vent the crankcase line to the atmosphere for the winter, putting it back in the spring.
He did mention that some of the new bimmers have an insulating pad around the evaorator, but he doesn't know if it can be retrofitted.

As for cost of repairs, he doesn't know why a seperator would be replaced unless freezing caused it to deform in some way. In his shop replacement of the sepeator would run about $700 taxes paid. A valve cover gasket would be extra as would a pan gasket or what ever else needed replacement.

My two cents worth is that cold in my part of the world is normal so we ignore BMW whenvthey tell us that we do not need block heaters. There is one that fastens to the outside of the block that runs about $200 installed and as far as I'm concerned it is worth every penny. I have also installed a 2 amp Battery tender that plugs in with the block heater and I never have starting problems. I also let my car run for a few minutes before driving away and I try and make sure trips are for at least half an hour. So far I've been doing all right and my maintenace costs are quite low as a result.

I hope this helps

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    • Re: oil separator ruined engine???? - dblnomad 2008-01-14 11:42:39 (603 views)
      • Re: oil separator ruined engine???? - renny 2009-02-03 22:47:58 (211 views)