oil separator symptoms

[juppalgae]

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

[JCL]

It may help those new to this issue to know the failure mode for the oil separator. The oil separator failing doesn't cause the problem. Primetime outlined this above, but here is a bit more detail.

All engines get condensation inside them, worse in cooler weather. When you get the engine good and hot (30+ minutes, preferably more), the condensation burns off. If you only do lots of short trips, it never burns off, and it builds up. It forms a milky paste that is visible under the oil filler cap. If you don't have this build up of condensation, the oil separator is not going to be an issue until the rubber hoses go soft, usually in 5 years or so (similar to rad hoses).

If you drive for long enough with the condensate building up, it collects in the oil separator. Still no problem.

Now, if you have that buildup, and it gets very cold, the condensate can freeze in the separator (since it has water in it). That is what is being referred to as the separator failing. It isn't really failing, it is just freezing. It isn't even freezing itself, the gunk inside it is freezing.

The insulated separator has a higher tolerance for low temperatures before it freezes, but it doesn't solve the problem (the condensate), it just tolerates colder temperatures. Personally, I have never had a separator freeze (even in -30C), but then I don't tolerate lots of short trips as that is very hard on the vehicle.

Even if you have the new and improved separator, it is worth checking the separator every few years (not sure what interval is right for each individual) to see if condensate is building up there. If so, clean it out. That is the best preventative measure, even better than putting the new design parts on. Eventually the separator will fail (rubber goes soft) and then it is a toss up if the new and improved one is worth doing or not. Can't hurt.

Hope this helps those who are trying to figure out what to do after an OSV freeze up.

[sfcl]

Originally Posted by JCL

It may help those new to this issue to know the failure mode for the oil separator. The oil separator failing doesn't cause the problem. Primetime outlined this above, but here is a bit more detail.

All engines get condensation inside them, worse in cooler weather. When you get the engine good and hot (30+ minutes, preferably more), the condensation burns off. If you only do lots of short trips, it never burns off, and it builds up. It forms a milky paste that is visible under the oil filler cap. If you don't have this build up of condensation, the oil separator is not going to be an issue until the rubber hoses go soft, usually in 5 years or so (similar to rad hoses).

If you drive for long enough with the condensate building up, it collects in the oil separator. Still no problem.

Now, if you have that buildup, and it gets very cold, the condensate can freeze in the separator (since it has water in it). That is what is being referred to as the separator failing. It isn't really failing, it is just freezing. It isn't even freezing itself, the gunk inside it is freezing.

The insulated separator has a higher tolerance for low temperatures before it freezes, but it doesn't solve the problem (the condensate), it just tolerates colder temperatures. Personally, I have never had a separator freeze (even in -30C), but then I don't tolerate lots of short trips as that is very hard on the vehicle.

Even if you have the new and improved separator, it is worth checking the separator every few years (not sure what interval is right for each individual) to see if condensate is building up there. If so, clean it out. That is the best preventative measure, even better than putting the new design parts on. Eventually the separator will fail (rubber goes soft) and then it is a toss up if the new and improved one is worth doing or not. Can't hurt.

Hope this helps those who are trying to figure out what to do after an OSV freeze up.

Hi JCL, you are all right of course however some people could have a tendency to think that it is just necessary to clean the OS, not to replace it. Although this is often true, in my own case I wouldn't have been able to clean it, too much hard deposit inside, I'll try to post pictures of the open old OS when I can. New OS is cheap (50 to 60 dollars usually) and most probably one of the hoses or their o-rings will fail during the removing process, so I guess that the best way would be to replace it with its hoses, worth it when you spend not less than 3 or 4 hours to do the job (at least for me!).

[JCL]

Originally Posted by sfcl

Hi JCL, you are all right of course however some people could have a tendency to think that it is just necessary to clean the OS, not to replace it. Although this is often true, in my own case I wouldn't have been able to clean it, too much hard deposit inside, I'll try to post pictures of the open old OS when I can. New OS is cheap (50 to 60 dollars usually) and most probably one of the hoses or their o-rings will fail during the removing process, so I guess that the best way would be to replace it with its hoses, worth it when you spend not less than 3 or 4 hours to do the job (at least for me!).

I believe there is a seal kit available for the separator (at least some models of it). I agree that when it is opened up, if it needs seals then it is a choice of resealing it or replacing it. My intended comment was that if you have new parts on it, it isn't necessary to replace it every year, but rather to clean it out. It does have a finite life, however, and at any piont replacing it may just be easier.

[juppalgae]

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

[JCL]

Originally Posted by juppalgae

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

How would we know? You gave the link to REALOEM above. Simply look up both models. Same part number means it the same item. Not sure why it matters, unless you have a stock of E46 separators to use up. This issue is in no way specific to the X5, but is common to many BMW models.

[primetime]

Originally Posted by juppalgae

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

Call up your dealer and ask them..problem solved..

[sfcl]

About OS, I forgot to mention something interesting: I had at home a whole OS and hoses set, Contitech brand for the hoses, Febi por the OS, that I purchased some months ago. Once I decided to replace the whole system, I wondered if it wouldn't be better to get genuine BMW parts (means supposed better quality) as this is not the job that I'd like to do every month!
So I ordered a set of brand new BMW OS and hoses and tried to do the job. It took a little more than one hour to get the old OS out, no problem except that I had to cut the old hoses (brittled) to get them out. And it took about 2 hours to only try to put the small "S" hose coming from the OS to the valve cover (the one which needs to be rotated)!! No way to click the hose on the OS, even with some silicone lubricant. It was already hard to fit with the OS outside of the vehicle and simply impossible to fit on the car... After 2 unsuccessful hours, I got the Contitech parts and immediately noticed that the design was far more better! Put them on the vehicle and after one or two tries, the hose came to the right place with no real effort...
I got a look after that to the BMW parts when I had more time. To get the hose on the OS easily, I finally needed to use a file to slightly reduce the int. diameter of the clip ring...
I don't know if it was a bad batch of parts ot whatever but it could be helpful for those who plan to replace the OS and get the same problem.

[we350z]

This is an excellent explanation and very informative. Thank You.

Originally Posted by JCL

It may help those new to this issue to know the failure mode for the oil separator. The oil separator failing doesn't cause the problem. Primetime outlined this above, but here is a bit more detail.

All engines get condensation inside them, worse in cooler weather. When you get the engine good and hot (30+ minutes, preferably more), the condensation burns off. If you only do lots of short trips, it never burns off, and it builds up. It forms a milky paste that is visible under the oil filler cap. If you don't have this build up of condensation, the oil separator is not going to be an issue until the rubber hoses go soft, usually in 5 years or so (similar to rad hoses).

If you drive for long enough with the condensate building up, it collects in the oil separator. Still no problem.

Now, if you have that buildup, and it gets very cold, the condensate can freeze in the separator (since it has water in it). That is what is being referred to as the separator failing. It isn't really failing, it is just freezing. It isn't even freezing itself, the gunk inside it is freezing.

The insulated separator has a higher tolerance for low temperatures before it freezes, but it doesn't solve the problem (the condensate), it just tolerates colder temperatures. Personally, I have never had a separator freeze (even in -30C), but then I don't tolerate lots of short trips as that is very hard on the vehicle.

Even if you have the new and improved separator, it is worth checking the separator every few years (not sure what interval is right for each individual) to see if condensate is building up there. If so, clean it out. That is the best preventative measure, even better than putting the new design parts on. Eventually the separator will fail (rubber goes soft) and then it is a toss up if the new and improved one is worth doing or not. Can't hurt.

Hope this helps those who are trying to figure out what to do after an OSV freeze up.

[JCL]

Originally Posted by we350z

This is an excellent explanation and very informative. Thank You.

You are very welcome.