increasing oil consumption

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I've noticed a steady increase in oil burning over past couple years. 1200-1300 miles between adding quarts a couple years ago to now 700. What are the most likely suspects? Seems to be more consumption/burning than leaking while idle because at one point recently it was not driven for awhile and I noticed no change in oil level at all. Plus this decrease in oil efficiency has been remarkably steady and gradual.

2006 525XI, 140,000 mi, and I use 5W-30 synthetic.
 
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Which brands of oil have you been using? What was your oil change interval? What kind of driving routine?
 
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Don’t know anything specific about your car however I’d start by ensuring that the PCV system and vent is clear and operating as designed, air filter isn’t clogged, oil drain back holes aren’t blocked with sludge, and last run some Berrymans through the intake, in the fuel, and several short oil changes for stuck rings.
 

sparkyjonze

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Which brands of oil have you been using? What was your oil change interval? What kind of driving routine?
Mobil 5W-30 synthetic. That hasn't changed. Most usage is about 5-15 mile trips. 400-500 miles per month. Oil change history about every 5000 mi.
 
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I've noticed a steady increase in oil burning over past couple years. 1200-1300 miles between adding quarts a couple years ago to now 700. What are the most likely suspects? Seems to be more consumption/burning than leaking while idle because at one point recently it was not driven for awhile and I noticed no change in oil level at all. Plus this decrease in oil efficiency has been remarkably steady and gradual.

2006 525XI, 140,000 mi, and I use 5W-30 synthetic.
check the PCV, they are known to fail and to cause oil consumption

 
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I would verify good, strong vacuum present at the PCV valve and a clear breather filter element if so equiped.
 
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You'll get 50 replies about PCV valve which is rarely the reason (but relatively easy and not expensive to replace). It seems your engine (piston rings) are gradually wearing out more allowing more oil to burn in combustion chamber. IF there are no new leaks. There is no special consumption ghost invaded your engine.
2 years are not 2 days.
 

sparkyjonze

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I would verify good, strong vacuum present at the PCV valve and a clear breather filter element if so equiped.
Thanks for checking in. That's a little bit more involved on an N52 engine isn't it? How do I test?
 

sparkyjonze

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Don’t know anything specific about your car however I’d start by ensuring that the PCV system and vent is clear and operating as designed, air filter isn’t clogged, oil drain back holes aren’t blocked with sludge, and last run some Berrymans through the intake, in the fuel, and several short oil changes for stuck rings.
"the PCV system and vent is clear and operating as designed"

Is there a way to test that doesn't involved taking everything apart? Thanks for your input.
 
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You'll get 50 replies about PCV valve which is rarely the reason (but relatively easy and not expensive to replace). It seems your engine (piston rings) are gradually wearing out more allowing more oil to burn in combustion chamber. IF there are no new leaks. There is no special consumption ghost invaded your engine.
2 years are not 2 days.
Then there is one reply which offers little help. Where I come from, you check the easy , cheap areas first before you condemn the engine. Make sense?? He didn't mention a decrease in performance which I would expect from worn out rings. Worn valve seals would be much more likely than worn out rings .
 
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"the PCV system and vent is clear and operating as designed"

Is there a way to test that doesn't involved taking everything apart? Thanks for your input.
I’ve checked them before by placing my hand over the oil filler hole to see if there is a slight suction. This while the engine is idling. A really dirty air filter element can cause an engine to use more oil as well as elevated operating temps. Sludge clogging the oil drain back passages in the head will allow oil to flood/puddle around the valve stems and be drawn in the cylinders via the valve guides. The rings could be stuck. Berrymans down the intake while running and a can poured in the fuel tank. In the end, the engine/rings just could be worn to the point of loss of oil control. IN MY OPINION.
 
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