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Volkswagen Jetta 2.5: Only For Certified VW Jetta 2.5 Expert

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Only For Certified VW Jetta 2.5 Expert - Burning Oil

2006 VW Jetta 2.5 Automatic. 78k miles.

Our friend's Jetta seemed to be consuming more oil than normal, but without noticeable smoke. Tow days ago, it was left at idle in the driveway for about 25 minutes, on a hot day (93F/34C), and it suddenly started putting out lots of oil smoke from the exhaust. It had an oil change with synthetic in the correct spec a day earlier, but was fine after the change. On the day of this trouble, it also had a full 6 hour detail/clean-up, but no water was put into the engine bay, only wiping, and it drove home fine for 10+ miles. Our friend says there is no history of any exhaust smoke, so this appears to be a one time/first time event.

When it was restarted today at our independent shop, cold from overnight, the massive oil smoke was exactly the same.

The temp gauge was normal while it was smoking, and it did not appear to be overheating.

What is the most usual or most likely problem on this car with 78k?

And does leaving this otherwise seemingly well running car to idle in hot temps seem to point to a particular issue?

Do you think the head gasket failed, or is starting to show failure by idling in hot temps?

Or a valve seal?

Is PCV possible?

**Expert Chris kindly advised : There is a breather system built in to the valve cover that is separate from just the PCV. When it is hot, there is more pressure build up. When the diaphragm fails it sucks up oil instead of combustion gasses, which is causing the smoke. These engine do burn oil but usually not enough to cause the amount of smoke you are describing. If there is a problem with the engine, a compression test or cylinder leak down test would isolate it to specific cylinders. But i have replaced several valve covers for this issue.

1. Our shop has already replaced the PCV, and reportedly had a source for changing the breather diaphragm in the valve cover, which they did do. I was not aware this could be changed changed successfully, without replacing the valve cover. Does anyone know for sure?

In any case, this did not immediately stop the oil burning and smoking. They decided to let the car run for a while to burn off any accumulated oil, and maybe give it a drive. That is the last I have heard.

2. How long, realistically, could it take to burn up any accumulated oil?

3. My understanding is that there is a second PCV type device located in the oil filter housing that could also be an identical cause of this type of problem, just like the PCV/breather in the valve cover. Have any VW techs seen this? Is it a likely culprit?

4. Although I have not spoken with the lead tech, the assumption is that they already know this is intake-related oil burning issue, likely affecting all cylinders, not an individual cylinder or cylinders, indicating possible rings or valve seals.

5. Anything else to consider?

6. As a side note, would you recommend any other maintenance items for 78k, since they already have some pieces out of the way? Air filter? Timing chain? Or not necessary yet. I hear the 06 chain and guide is a defective part. Is it a bulletin/recall?

Thanks Much.

chris : I have never seen a kit to replace the diaphragm in the valve cover the cover is relatively inexpensive part it is made of plastic. As far the smoking if they did replace what they say they did perhaps the engine oil was overfilled causing it to get past the rings. If this the case I would pull the spark ifs to see if they have oil on them. If they are all wet most likely overfilled oil at some point if only one is wet then you could be looking at a mechanical problem in one cylinder. At 78k you are coming up on a major service performed at 80 replacing spark plugs air filter cabin filter oil change and tire rotation. The chains don't have a service interval and it is quite a bit work and the parts are expensive to just swap out

Thanks. I wanted you to answer those questions, but didn't think you could get any more credit on the same I posted fresh. Since that post, the shop advised that on initial inspection, all cylinders were affected, so a top down oil source was suspected (vs rings/valves in one cylinder). He claimed to experience excess vacuum, so he went ahead with the PCV replacement and replaced the breather diaphragm in the valve cover (still not sure if this is a good fix, nor where they got this part...I've only heard of replacing the whole valve cover). Anyway, it was still smoking upon start they thought it might take a while to clear out. I think they went ahead and cleaned up the oil in the intake/throttle in some way...and... it to STOP smoking. But when they ran it (or drove it?), the smoking eventually returned.


At this point, I think they started to give up, wanting to claim internal problems...blow by...wash hands...take to dealer...which did not sit great with me. I mentioned the secondary PCV-like system in the oil filter housing, which I've read can cause the same problem as the PCV/breather in the valve cover.


They were not aware of this second system, and went back to look after it. That was 1.5 hours ago, so perhaps they are on to something.

chris : Hopefully they find something and its an easy fix. If does end up being in the cylinder head and the head has to come off then I would replace the chains and guides since all that has to come off anyway

I'm thinking it shouldn't be too hard for them to isolate these two PCV vacuum situations, and figure out which is causing the problem.


Have you seen the same problems with that second PCV system, in the oil filter housing? Just much less often than the valve cover? It seems lots of codes and problems are related to the darn valve cover, no?

chris and 5 other VW Specialists are ready to help you
Customer: replied 3 years ago.

Hi Chris. I tried to direct a new question to you...twice. But they keep posting as all experts. Anyway, there are two hanging out there. If you can grab both for credit, great. Thanks.

Customer: replied 3 years ago.

Hi Chris. I have a new question for you specifically, but the system won't allow it to be directed to a particular has already been asked to the whole group. So, I will put it here, and add new credit when you reply. Hope all is well.


Most of our mechanical repairs, problems, and maintenance have been resolved. Here is the latest:


2006 Jetta 2.5 with 6spd Automatic (non-DSG) transmission. 77k miles:


The trans used to have about a 3 second delay when shifting from park to the morning when cold. In the past 3 weeks, this delay has increased a lot. Tested this morning: 50-55F degrees. First start of the morning. Shifted immediately to D (not Sport or +/- manual), the started a stopwatch. 9-10 seconds before drive started to engage.


The VW dealer says this is not abnormal, and that many customers report the same experience. The dealer says it is a truly sealed unit (sealed for life), and you do NOT service this transmission at all (no fluid changes, etc.). There is no dipstick.


Other say 3 seconds is fine, but not 9-10 way.


The transmission seems to operate perfectly once warmed up, and shifts smoothly and reasonably quickly up and down whether automatically or manually.


I did note an odd nuance that, even when dead cold, if I pull the shifter over into the manual shift mode (+ and -), it will engage immediately into forward, without the 9+ second delay experienced when shifting from park to drive.


Either the colder morning temps are affecting this trans, but to a higher than acceptable level. Or perhaps there was some collateral damage during one of the many other repairs. Maybe someone knocked a trans hose loose, and then replaced it, spilling some fluid. Who knows?


Any explanation? What should we do? Thanks

Generally a delay when cold is a fluid level issue a 9 second delay is abnormal. I would bet you have a low fluid level there is no dipstick to check though you need a scan tool to check the fluid level. While there isn't a maintenance interval for the trans the first thing I would try is draining the trans and refilling it to the proper level you may have a leaking pan gasket or most likely in this model the transmission valve body has been replaced at some point in its life
Customer: replied 3 years ago.

I went to the VW dealer where I know the manager, and the tech. There were no trans leaks/seeps, and no trans codes in the module. He said the trans fluid needs to get down to a certain temperature (cool off) before he can accurately check the we couldn't do that today, since I had been driving it...and it was way too hot. I'm guessing the fluid is probably a little low, and the increase in cold shift time over the past three weeks is probably due to the colder morning weather. I'm not sure if we will pursue this further. My friend is selling this car, and I'm not sure about opening up the sealed system at the point. The tech said that as this NON-DSG sealed trans approaches 100k, they recommend NOT opening it up or changing fluid at all. The fresh fluid seems to cause more problems than it solves. I'm just passing on what he said.

If they are thinking of getting rod of it I probably wouldn't put any more money into it. Draining the tranny is always a little risky I would leave it alone you don't want to open a can of worms right before selling it
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Customer: replied 3 years ago.

As always, thanks Chris. I will rate excellent.

Thank you and good luck

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