Oil in intake, poorly designed DI/turbo system?

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167
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ID, US
This is my 2007 Mazda CX7 with a 2.3l 4 cylinder direct injection turbo engine with 11,000 miles. I pulled off the intercooler to clean some things and this is what I find. The speculation is PCV system and maybe an oil catch can would help... but I can't help but think why a manufacturer would think this is an acceptable engine design? There is a puddle of oil/contaminants in my intake right before the throttle body lol. Cold side of intercooler After intercooler, right before throttle body.
 
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1,877
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Pacnw
Dah! That's nuthin. Take a look at this person's intake valves at 80k miles. You guessed it, from pcv gunk. On a vw DI turbo I did this PCV bypass DIY to get rid of pcv gunk on mine. MPG and power have went up slightly and car runs the best it ever has. No increase in oil consumption. But only have about 900 miles on it since bypass including high speed cruise, 0-60 and 1/4 mile times so not a good test of oil consumption yet. Ill be doing UOAs at 2700 and 5k miles to see if any affect on oil.
 
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1,798
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Saint Paul (ex-San Diego)
 Originally Posted By: astraelraen
This is my 2007 Mazda CX7 with a 2.3l 4 cylinder direct injection turbo engine with 11,000 miles. I pulled off the intercooler to clean some things and this is what I find. The speculation is PCV system and maybe an oil catch can would help...
Why do you blame the injection system or the turbo in the thread title, if the problem is the PCV? If you have a problem, fix it. Don't just complain about the design. Don't all modern engines have PCV's?
 

Kestas

Staff member
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This is a known issue in the engine industry, especially for turbo engines. There is a company called Parker Hannifin that is developing a range of closed crankcase ventilation systems that will coalesce and separate oil mist, soot, and liquid volatiles from crankcase gases, and return them to the proper stream. Unfortunately, this will probably appear in the truck market long before it'll appear in the automotive market.
 
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14,776
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Illinois
Nice welding job on the inner cooler. I recently repaired one on a diesel 42 ft RV. Saved him tons of money.
 
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3,756
Location
CA
PCV or turbo. I've had some new turbos that always left a light mist of oil in the intake tract and some that left the intake completely dry and free of oil. Looking at how nice and clean the oil looks, I would guess it's coming from the turbo.
 
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1,007
Location
Dallas, TX
Turbo seals are notoriously troublesome on this engine. Lots of folks with Mazdaspeed 6s and Mazdaspeed 3s are having turbos replaced under warranty due to excessive blue smoke out the tailpipe after extended idling. Most of these engines have had aftermarket exausts put on, which for some reason (reduced backpressure is the theory) causes the turbo seals to begin weeping oil into the intake, but some are bone stock. The situation you're in is that you've disassembled part of an engine that is (?) still under warranty, so they may balk at covered repairs. What I'd do if I were you is button it back up and wait for the smoking to begin. To hurry the process along, take it for a long drive, then let it sit in the driveway idling for 20-30 minutes. If you get smoke, take it in. Take a video or picture of the smoke to avoid "unable to duplicate" B.S. at the dealership.
 
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6,146
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Illinois
 Originally Posted By: Kestas
This is a known issue in the engine industry, especially for turbo engines. There is a company called Parker Hannifin that is developing a range of closed crankcase ventilation systems that will coalesce and separate oil mist, soot, and liquid volatiles from crankcase gases, and return them to the proper stream. Unfortunately, this will probably appear in the truck market long before it'll appear in the automotive market.
I made my own.
 
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1,904
Location
Canada
Run a good quality synthetic, and don't change it more than is really necessary (ie: depends on car, but 20-30k mile oil changes are reasonable for most cars on the road today with good synthetics). That'll take care of most of the 'problems' relating to oil vapours coming through the PCV. The people who do 3k mile oil changes on dino are really causing lots of problems because brand-new oil has a lot more 'boil-off' components, especially dino oils, compared to synthetics. Changing oil too often can be, as some of the above photos show, very harmful to an engine.
 
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Pacnw
 Originally Posted By: pitzel
Run a good quality synthetic, and don't change it more than is really necessary (ie: depends on car, but 20-30k mile oil changes are reasonable for most cars on the road today with good synthetics). That'll take care of most of the 'problems' relating to oil vapours coming through the PCV. The people who do 3k mile oil changes on dino are really causing lots of problems because brand-new oil has a lot more 'boil-off' components, especially dino oils, compared to synthetics. Changing oil too often can be, as some of the above photos show, very harmful to an engine.
The photos I posted did NOT have build up from changing the oil too often. Changing not often enough could perhaps be a factor though. Mainly it is from DI design itself. Most oils, including GC, are shot by 5k in the vw 2.0FSI engine and it would be absolutely foolish to run an oil 20k in that application IMO.
 
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Canada
 Originally Posted By: saaber1
Changing not often enough could perhaps be a factor though. Mainly it is from DI design itself. Most oils, including GC, are shot by 5k in the vw 2.0FSI engine and it would be absolutely foolish to run an oil 20k in that application IMO.
What does VW spec in Europe? 30k OCI's on that engine? And what's so great about "GC"? Seems to be just an average oil with an above-average price every time I've looked at the UOA's.
 
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1,346
Location
Texas
 Originally Posted By: pitzel
The people who do 3k mile oil changes on dino are really causing lots of problems because brand-new oil has a lot more 'boil-off' components, especially dino oils, compared to synthetics. Changing oil too often can be, as some of the above photos show, very harmful to an engine.
What in the world are you talking about?
 
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1,010
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South East Asia
Originally Posted By: pitzel
Run a good quality synthetic, and don't change it more than is really necessary (ie: depends on car, but 20-30k mile oil changes are reasonable for most cars on the road today with good synthetics). That'll take care of most of the 'problems' relating to oil vapours coming through the PCV. The people who do 3k mile oil changes on dino are really causing lots of problems because brand-new oil has a lot more 'boil-off' components, especially dino oils, compared to synthetics. Changing oil too often can be, as some of the above photos show, very harmful to an engine.
Synthetic does not boil off much, but non low-SAPS oil will create more deposits when it really boil-off. So for DI, the compromise is to use good low SAPS synthetic oil and hopefully does not need to clean up intake so often
 
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2,039
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Jupiter, Fl
The first set of pictures look pretty normal. Many modern cars allow a little liquid oil into the intake through the PCV system. Some cars, like my Infiniti, end up with puddles of oil that sit in the manifold, but still use almost no oil. This is where the advantage of a catch can comes in, to keep this out of the intake.
 
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468
Location
new Jersey
What does VW spec in Europe? 30k OCI's on that engine? Try 30,000 KILOMETERS ... not miles ! If you didn't know that your credibility is suspect .
 
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436
Location
USA - Southern California
On turbo's that I've seen, oil at the inlet to the turbo and in the intercooler is common. It happens on my Supra Turbo. The problem on a turbo is that manifold "vacuum" can go to boost, so when you're boosting, where would the "PCV" vent? I don't think it has anything to do with DI.
 
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