Hello, I recently purchased a 2.8 liter V6 Passat from a local dealer Califorania dealer. It had recently passed smog and seems to run flawlessly. However, I've come to discover that it burns a tremendous amount of oil (about a quart every 1000 miles, maybe even more). I don't see any smoke coming from the tail pipe. I can't for the life of me imagine how it could have passed smog, run without smoking and burn that much smoke. Now I'm very worried that there is something terribly wrong with the engine.
I would very much appreciate if you might be able to give me some ideas about what the problem could be, how serious it might be, and why I should/might do about it.
Have the spark plugs checked to see which cylinders are affected.
Oil leaks are common on these engines, so have that checked as well.
January, 9, 2013 AT 3:37 AM
My mechanic just replaced the spark plugs. Hmm. Also, the engine check light keeps coming on every few days and then goes off for a few days, around and around.
Is the fact that I don't see large amounts of smoke out the back end a strong indication that it is not, in fact burning oil?
Thanks very much.
January, 9, 2013 AT 3:49 AM
If your plugs had been fouled, your mechanic would have mentioned it. Although, oil burning can leave little trace if at the right quantity.
Leaks should have been evident as well if present.
Not knowing what the codes are, I can't suggest repairs for the check engine light issue.
January, 9, 2013 AT 3:53 AM
Yes, on the day that I took the car in to have him look into the problem, the light decided to no be on. So, I assume that unless the light is on, it will not output error codes. Anyway, he said the plugs hadn't been changed in a long time. But, he didn't say anything about fowling and didn't have any ideas about where the oil might be going.
Can significant amounts of oil burn without smokeing?
I guess I just have to wait until the light goes on permenantly before taking it in again?
Can a car pass smog if it's burning significant oil? It did pass smog recently?
If it is burning oil, will that destroy the catalytic converter in short order?
Thanks very much.
January, 9, 2013 AT 4:02 AM
Catalytic converters can hide oil burning and in the long run be damaged because of it.
.5q per 600miles is an acceptable amount according the vw.
Codes remain in memory for a while after the light is out. I scan every car I work on regardless of the light being on or off.
Have the pcv system checked as it can contribute to leaks and oil burning.
January, 9, 2013 AT 4:07 AM
Oh my Gosh. So, the cat may actually be soaking up the burned oil which is why it was able to pass smog and I'm not seeing any smoke?
Wow! So.5q per 600 miles means I've literally got to add oil every few trips to the gas station? I've never had anything but old cars and none of them has ever burned any significant oil.
Ok. I'll ask the mechanic to check the pcv.
In any case, it sounds like the car will run as is for quite some time. Yes?
Thanks so much for your help.
January, 9, 2013 AT 4:15 AM
At 10yrs old, expect to put money into it. But it should still last you another 10.
Use synthetic oil, I nave seen oil usage drop when switching to synthetic.
If you don't see oil leaks or stains on the drive way, then the oil has to go somewhere. Burning is the next obvious place to check.
Stick with a mechanic who is familiar with vws so that you can feel confident with the service.
January, 9, 2013 AT 4:30 AM
If it turns out to be burning oil, does that most likely mean rings or valve guides? I'm thinking that would be a $5000 repair job to fix it properly. Not sure I can afford that. Could I just drive the car like that for years?
January, 9, 2013 AT 4:47 AM
Spend a bit of money on diagnosis so that you at least confirm your suspicions. Yes, you can drive it like that as long as you keep the oil topped up. Eventually it will fail the emissions test, at which point new catalytic converters might get it through another year.
If you are lucky, a simple pcv repair will reduce the usage.