Coollant leaking into oil system?

Ghost-Flame · #1 10-02-2009, 10:21 AM

Don't flame me if this has been asked before... I did a search and couldn't find anything.

I think I read here at this forum that a milky condensation on the oil fill cap is a sign that coolant is leaking into the oil.

2 day ago I scrubbed my oil cap with wd-40. I got every trace of crude off of it and today after about 100 miles I have a milky something around the inside of the cap.

Now assuming this car hasn't been with any dirty little Hoes (lol), what would you say is causing this?

The car is an 2002 3.oi with 95,000 miles on it. The engine was abused before I got it @82,000 miles (the old oil from my first change looked like it had never been changed... no kidding it plopped out like liquid pudding) . I have changed the oil 3 times in 13,000 miles
w M1 EF 0w-40 to clean it out. Each time it gets progressivly cleaner looking. this current oil has 3,000 mile on it. I am going to go to 7500 oci. The engine uses about 1 quart in 1800 miles. other wise the car runs great.

what tests should be preformed etc?

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motordavid · #2 10-02-2009, 11:36 AM

See the linked thread, esp. page 2 onward...
Probably oil serpator valve & related hoses.

And, using Search Tab should yield pages of
threads related.
GL,mD

http://www.xoutpost.com/bmw-sav-foru...valve-diy.html

primetime · #3 10-02-2009, 12:30 PM

Motordavid is correct. This is your oil seperator/crankcase valve issue. Stop using wd -40 to clean the oil cap, its not needed and serves no purpose. Wiping off the "cheese" simply needs a paper towel nothing more. The problem isn't the oil cap, its your crankcase that has built up too much pressue not allowing the oil to reach proper temps to burn off the condensation. This is due to short trips under 20 or 30 minutes. Sounds like a raw deal I know. But that is the culprit in descriptions similar to yours. If you do not take care of this, One cold morning your valve cover gasket will blow, and your engine will billow out tons smoke while you're driving to work on the freeway in nice freezing weather and oil will be spraying all over your engine bay.

Ghost-Flame · #4 10-02-2009, 05:22 PM

Quote:

Originally Posted by primetime

Motordavid is correct. This is your oil seperator/crankcase valve issue. Stop using wd -40 to clean the oil cap, its not needed and serves no purpose. Wiping off the "cheese" simply needs a paper towel nothing more. The problem isn't the oil cap, its your crankcase that has built up too much pressue not allowing the oil to reach proper temps to burn off the condensation. This is due to short trips under 20 or 30 minutes. Sounds like a raw deal I know. But that is the culprit in descriptions similar to yours. If you do not take care of this, One cold morning your valve cover gasket will blow, and your engine will billow out tons smoke while you're driving to work on the freeway in nice freezing weather and oil will be spraying all over your engine bay.

Thanks, another downfall of German overengineering? when a simple pcv might have done the job.

I will order one and put it on while I'm in there replacing the water pump and all related belts hoses and doo dads.

JCL · #5 10-02-2009, 05:56 PM

Quote:

Originally Posted by primetime

Motordavid is correct. This is your oil seperator/crankcase valve issue. Stop using wd -40 to clean the oil cap, its not needed and serves no purpose. Wiping off the "cheese" simply needs a paper towel nothing more. The problem isn't the oil cap, its your crankcase that has built up too much pressue not allowing the oil to reach proper temps to burn off the condensation. This is due to short trips under 20 or 30 minutes. Sounds like a raw deal I know. But that is the culprit in descriptions similar to yours. If you do not take care of this, One cold morning your valve cover gasket will blow, and your engine will billow out tons smoke while you're driving to work on the freeway in nice freezing weather and oil will be spraying all over your engine bay.

Agree with all the above posters on the general theme here, but I don't agree that this is caused by the oil separator. We are confusing cause and effect here.

Milky oil is caused by water/coolant in the oil. If the oil is milky when you check the dipstick you are looking for a coolant leak, ie headgasket or something similar. If the oil is dark, but the milky paste is under the oil filler cap, then it is still caused by moisture, but it is likely caused by condensation (small amount of moisture, and localized). The root cause of this is short trips that don't allow the engine to fully warm up. The engine goes through multiple cooling/warming cycles in this case, and each time the condensation forms, mixes with the oil, and causes this paste. The solution is to ensure that when you use the vehicle, the oil gets hot enough to boil off the condensation. While the usual cause is too many short trips, a thermostat not functioning correctly could theoretically contribute to the problem.

When the paste is produced, over time it usually collects in the crankcase oil separator (which is like a PCV). That doesn't cause a pressure buildup. If it freezes due to the water vapour in the paste (not likely in September/October) then the separator is blocked, then you get the pressure buildup, and then you will likely have a failed valve cover gasket (as the pressure blows out through the weakest gasket).

The pressure buildup does not cause the paste, it is the other way around, and then usually only if it freezes.

What I do agree on is that if you have this paste, then it is worth checking your oil separator to see if it is filled and may become frozen this coming winter. I just don't agree that the separator causes the paste.

Primetime, it may just be a wording issue, as I know you have been through this problem yourself

Ghost-Flame · #6 10-02-2009, 07:37 PM

Quote:

Originally Posted by JCL

Agree with all the above posters on the general theme here, but I don't agree that this is caused by the oil separator. We are confusing cause and effect here.

Milky oil is caused by water/coolant in the oil. If the oil is milky when you check the dipstick you are looking for a coolant leak, ie headgasket or something similar. If the oil is dark, but the milky paste is under the oil filler cap, then it is still caused by moisture, but it is likely caused by condensation (small amount of moisture, and localized). The root cause of this is short trips that don't allow the engine to fully warm up. The engine goes through multiple cooling/warming cycles in this case, and each time the condensation forms, mixes with the oil, and causes this paste. The solution is to ensure that when you use the vehicle, the oil gets hot enough to boil off the condensation. While the usual cause is too many short trips, a thermostat not functioning correctly could theoretically contribute to the problem.

When the paste is produced, over time it usually collects in the crankcase oil separator (which is like a PCV). That doesn't cause a pressure buildup. If it freezes due to the water vapour in the paste (not likely in September/October) then the separator is blocked, then you get the pressure buildup, and then you will likely have a failed valve cover gasket (as the pressure blows out through the weakest gasket).

The pressure buildup does not cause the paste, it is the other way around, and then usually only if it freezes.

What I do agree on is that if you have this paste, then it is worth checking your oil separator to see if it is filled and may become frozen this coming winter. I just don't agree that the separator causes the paste.

Primetime, it may just be a wording issue, as I know you have been through this problem yourself

Thanks for clearing that up,

Here's my plan. I ordered a blackstone kit. I am replacing the water pump. Tstat and related hoses in the next couple weeks. I am going to take the oil seperator apart at the same time. I will clean it and if it looks really bad I'll replace w/hoses. does that sound logical and practical.

Ps the didstick looks good and normal. no milky goo.

JCL · #7 10-03-2009, 02:44 AM

Quote:

Originally Posted by Ghost-Flame

Thanks for clearing that up,

Here's my plan. I ordered a blackstone kit. I am replacing the water pump. Tstat and related hoses in the next couple weeks. I am going to take the oil seperator apart at the same time. I will clean it and if it looks really bad I'll replace w/hoses. does that sound logical and practical.

Ps the didstick looks good and normal. no milky goo.

Blackstone kit is a waste of time unless you are trending it over multiple samples.

Replacing the water pump has no connection with the condensate paste, but is not a bad idea at your mileage. Likewise the hoses, and may as well do the thermostat while you are there.

Agree with inspecting the oil separator; you will want to replace the hoses on it as well, as they go soft over time.

What you really need to do is give it a long run on the highway, and get it good and hot. Then change the oil again. Perhaps you want to try another oil and see if it produces less condensate paste.

Since the oil is not milky, you can conclude that this is caused by condensation, and not a water leak internal to the engine.

Ghost-Flame · #8 10-03-2009, 09:10 AM

Sounds like a plan.

I drive some short trips but never under 10 minutes the engine gets hot.

I use this car for driving in my real estate practice. every day the trips range from 10 minutes to 40 minutes. but every day it gets one of those long drives to really heat it up. I would say I do a mix of driving but the engine often doesn't have a chance to cool down after it is shut off.

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