3.0 hydrolock survival

[devitts032]

I hate to beat the oil separator deadhorse but I am feeling very lucky tonight. I just got a call from my mechanic and my 2003 95000k 3.0 is alive and well after my 2nd oil sep failure in 2 years this time with hydrolock. He was originally not very optimistic so I had already began researching and bracing myself for the cost of a replacement motor. After emptying the cylinders of oil and blowing out as much oil as possible and of course $150 worth of new oil sep parts it started and so far is not showing any residual problems. I called BMW NA as well as the dealer who fixed the first failure under my certified warranty. BMW NA cordually took my complaint without comment, help,or of course admission of any guilt. My dealer offered to replace parts they installed just less than 2 years ago but only if the problem was exactly the same and had the engine been damaged by the failure of their parts nothing for that. I know this has been discussed ad nauseum but it amazes me that BMW can and seems to want to get away without addressing this glaring bad and potentially dangerous design flaw. This is my second BMW and I am sad to say that my love affair is at least temporally suspended until this problem is fully addressed by BMW.

[JCL]

Glad to hear the engine appears to be OK.

Do you make many short trips that don't allow the engine to fully warm up? Any condensate (cream coloured paste) ever visible under the oil filler cap? If so, it is worth putting the oil separator and lines on your annual maintenance checklist. It is a lot cheaper than repairing damaged engines.

[devitts032]

I don't make alot of short trips but I did the night it most recently plugged. It is funny the first oil separater incident resulted in oil blowing all over the engine compartment while the most recent one siphoned 2 1/2 qts of oil into the crankcase with no visible problems under the hood except no oil on the dipstick. From reading I understand that it depends on what plugs in the system as to what the result is. I thought of exactly what you are saying about just changing the parts annually and in the end after I think some more about how much I love driving my X5 I may keep it and do the preventative parts swap each year.

[JCL]

The symptoms depend on whether the valve freezes in the closed position (pressurized crankcase, oil blows out through a gasket) or the open position (oil is drawn in to the intake manifold by vacuum, and then into the cylinders, creating a potential hydraulic lock).

You won't get a problem from a single short trip. If you don't get the oil hot enough to boil off the condensation each day though, over a longish period of time (I would say months), then the condensate forms, and can collect in the valve.

If I had the problem with the oil separator freezing (I never did, in any BMW I owned) I would then make it an annual check to ensure that the lines and valve are clear. They don't all need replacing each time, they just can't be clogged up with the condensate.

[devitts032]

Hey thanks I appreciate your knowledge. It is a great vehicle to drive in so many other ways I guess it is well worth some extra effort.

[JCL]

Originally Posted by devitts032

It is a great vehicle to drive in so many other ways I guess it is well worth some extra effort.

Once the foibles are known, then it isn't much extra effort IMO. If you see condensate forming under the oil filler cap, then it is likely in the OSV as well. If you make lots of short trips, it is even more likely. Do it for long enough, it collects enough to get close to blocking the OSV. Get a deep freeze, and it goes solid. There are lots of steps along that failure path for an owner to remedy it before having a catastrophic failure. And I think the payoff is worth it, it does drive very well.