2012 Jetta 2.5 repeat oil in intake

Matt Technical Support Specialist California Posted   Latest  
Resolved
Driveability
2012 Volkswagen Jetta Active 2.5L (CBUA) 5-spd
P0106 — Manifold Absolute Pressure/Barometric Pressure Sensor Circuit Range/Performance
P2188 — System Too Rich at Idle Bank 1
Check Engine Light

Hey everyone, I’m looking for a little advice on this one which has a bit of history to it.

This car has about 100k on it and came in originally a few months ago with the above codes. The tech replaced the MAP sensor at that time due to oil contamination and let it go. It came back a few weeks later with the same codes and oil pooled in the bottom of the intake. They then sent the car to a local dealer for a diag. The dealer verified that the pcm had the latest sw (there is a tsb) and recommended to replace the valve cover. The shop replaced the valvecover with an ”oe“ worldpac one, removed the intake and cleaned it, and cleaned the MAP sensor. Another few weeks go by and the car is back a third time with the same problem!

On Friday I looked at the car and verified that there is oil pooled in the intake again. I made sure that the purge valve is not leaking,I did a leak down with 5-7% leakage in each cylinder and didn’t see any wet pistons or other signs of blow by. There is 1” of vacuum in the crankcase during warm idle and the pipe from the valve cover to the intake is full of oil. Fuel trims look fine, cat is not plugged, injectors are not leaking, I’m ready to put a factory valvecover on it, clean the intake myself, and replace the MAP again. Am I missing anything obvious??

thanks in advance

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George Technician
Alabama
George
 

Have you checked crankcase ventilation system?

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Matt Technical Support Specialist
California
Matt
 

Hey George, As far as I can tell the only component in the pcv is the valve incorporated into the valve cover. I have 1” of vacuum in the dipstick which is dead on with other 2.5’s that I’ve worked on.

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Glenn Owner/Technician
Texas
Glenn
 

Use an OE valve cover Worldpac is an aftermarket at best. If it is a turbo model, the turbo shaft is shot and sucking oil.

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Matt Technical Support Specialist
California
Matt
 

Hi Glenn, This is one of the NA 5 cyl models, no turbo. A dealer v/c and MAP are the plan, just Trying to cover my bases thanks!

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Matt Technician
Ohio
Matt
 

what brand was it from worldpac? I am assuming Viaco? What faults have returned? if It’s just the p0106 I’d suggest a throttle body clean and adaption. Usually with these 2.5l my go to method was Software update (if needed) along with map sensor cleaning and throttle body cleaning. Usually works about 90% of the time. I have had issues with oil in the intake before however even with new OEM ones…

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Matt Technical Support Specialist
California
Matt
 

Thanks Matt, Both codes return everytime, sw is up to date. For what it’s worth this shop is 90 miles from my house, so a lot of this is over the phone. the throttle body has been cleaned and readapted and I can’t get it to fail in any way while I’m monitoring it. In your experience are there any drivability symptoms when the throttle body fails? Say a rough or high idle?The customer has not…

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Matt Technician
Ohio
Matt
 

No major symptoms usually. There use to be a old tech tip for early 2.5’s that the intake manifold bolts were back out and create small intake leaks.

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Stanley Owner
Pennsylvania
Stanley
 

Sounds to me like bad PVC which is in valve cover. Not a fan of aftermarket. PVC only place I know of that oil is induced into intake. Also common for them to fail on this motor. Crank case Vac. should be checked with a manometer not a vac gauge. I would also want O.E. Map sensor. Check oil may be loaded with gas. Good Luck

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Thomas Mechanic
Michigan
Thomas
 

Hello Matt, the recommendations to replace the valve cover with a genuine VW one(which includes the pcv valve) are excellent . I would, however, run the engine above idle, possibly 1800 rpm when fully hot, for several minutes, and check to see how much pressure is in the crankcase during those conditions. Also check the condition of the engine oil(is it dirty, black, heavily fuel-contaminated?)…

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Darren Technician
Oklahoma
Darren
 

Have you ever tried or heard of using automatic transmission fluid to clean the crankcase/oiling system ? Back in the 80’s I had an intermittent sticking lifter in a gm v8 causing a ticking at idle. I would change the oil and add 1 quart atf. In a few days or hundred miles the ticking would stop. I had to do this every year or 2. I fixed a few other cars with similar problems. ATF has a lot of…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Darren, Marvel Mystery oil is ATF on steroids with lots of detergents. I even recall flushing engines out with a ½ kerosene and oil mix. Just let it idle for a couple of hours with an occasional low RPM rev to splash it a little.

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Darren Technician
Oklahoma
Darren
 

I have heard of kerosene and diesel being used as flush but, I have never tried those. I have used diesel to free up stuck pistons in a engine that had been setting too long that had probably gotten some moisture into the cylinders.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Darren, The trick (reality) is not to run the engine at high RPM. Kerosene and diesel are very thin but still lubricate moving components. Back in past years past, older heavier built engines cold easily handle this flushing method. With modern engines, the coking sludge can be hard to get cleaned out and will often require engine replacement due to the cost of a teardown and overhaul…

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Sean Technician
California
Sean
 

I had an issue like this before and there was another oil trap on the engine block that you have to remove the intake to get to. If I’m remember correctly it was the 2.5l. assuming your new valve cover is good. hope This helps and I’m not misremembering.

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Michael Owner/Technician
New Jersey
Michael
 

Regarding your codes, check the MAP sensor wiring. i have seen it chafed within 6" of the connector. Use a factory valve cover.

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Obie Technician
Washington
Obie
 

Excellent posts so far. I would only add that the intake for the air cleaner be checked completely. A nest or rag in the ducting can cause similar symptoms.

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Paul Mechanic
Illinois
Paul
 

No actual experience with this model, but if engine has a history of using oil, outside of the excellent suggestions already listed, make sure customer is not overfilling oil with the idea of rather than checking oil level every fill up-over adding oil to extend intervals of having to check level.

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Stephen Technician
Oregon
Stephen
 

Squirt some brake kleen into the bell housing while monitoring additive fuel trim to check the rear main for vacuum leak causing manifold pressure increase and causing over fuel situation. This can be intermittent so difficult to reproduce in the bay without being driven.

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Mihail Technician
Maryland
Mihail
   

Matt, I am dealing with the same issue on a 2011 Jetta 2.5L. Car came with a permanent P0106 and a code for secondary air injection. No codes for rich mixture. I found the MAP sensor contaminated with oil and the PCV membrane on the valve cover torn. I replaced the PCV membrane on the valve cover with a dorman solution kit from Worldpack and also replaced the map sensor. Ran all basic settings…

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Matt Technical Support Specialist
California
Matt
 

You know what? Mine has a leaky vacuum pump too. I’ll Have the tech smoke it again with an eye on that. thanks!!

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Mihail Technician
Maryland
Mihail
 

I think mine is fixed. I changed the leaking throttle body seal and tightened the intake screws - they were loose. I also had the battery disconnected which may have helped reset things in the ECU. (I think the ECU was stuck on stupid yesterday with trims at negative 35 or more and the car running fine.) I test drove the car for ten minutes to warm it up and then set all monitors with a…

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Matt Technical Support Specialist
California
Matt
 

Thanks Mihail! I’ll let you know as soon as the guys finish the work. FYI, there is a “work around” for the vacuum pump without trans removal but it isn’t great

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Mihail Technician
Maryland
Mihail
 

Thanks and hope all goes well for you. Let me know what the work around is. I think I saw Worldpack has a vacuum pump repair kit with a gasket and a seal.

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Matt Technical Support Specialist
California
Matt
 

They want the trans removed because the shift lever is in the way. The vacuum pump can be removed if you take off the cover, then the guts, and finally the body. You might have to take the neutral safety off too, I forget. In the past I’ve always replaced the pump and just disassembled the new one and put it back together in the car. The reason that I say that it isn’t a great way to go is…

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Mihail Technician
Maryland
Mihail
 

Thanks for the tip - brilliant. I did not think about taking the pump apart. The pumps do look very similar as you say and they all leak at the cover. I don’t know if the repair kit for VW can be used on others but it is worth looking into it. I used silicone to seal off the cover of the vacuum pump on one of my cars and it worked pretty well.

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Matt Technical Support Specialist
California
Matt Resolution
 

The valvecover and MAP sensor were replaced with a factory parts and the intake was cleaned again. All the monitors were set after a few road tests as well. this car normally takes a few weeks to set the code so I’ll mark this resolved for now, if the car comes back again i’ll post something else or amend this if possible

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