Dirty PCV or something else?

slione · Post by **slione** » 07 Jan 2013, 14:32

I noticed my oil level dropped and looking under the car there appears to be oil leaking from someplace (have not yet traced the source). There is also "steam/smoke" that comes out when I open the oil filler cap but not out of the dipstick hole. From what I can tell reading posts here, these symptoms indicate a dirty PCV except that in all cases the telltale sign is smoke/vapor coming out of the dipstick and not the oil filler. There is a fair amount of "sludge" on the underside of the oil cap and the louvers in the filler hole (not sure if this tidbit is relevant or typical with a car that has 174K+ miles on it - I presume the latter).

Question 1: Am I diagnosing the PCV as the issue correctly or is there likely something else happening?

On a related topic, I recently bought the car (2002 XC70) and have no idea what type of oil is in it. There is a sicker on the windshield of a garage (Mobile) the PO used for the last oil change but I am still good for a thousand or so miles (and that is assuming the oil change reminder is based on a 3K mile interval). I am guessing it's synthetic since it was a Mobile garage but can't be sure. The oil on the dipstick is pretty clean but not new.

Question 2: Short of doing a whole oil change now vs. in a couple thousand miles, can I just top off with what is likely 10w-30 Mobile1 if what is in the car is not synthetic? The oil level is reading right at the "Min" level on the dipstick when cold. I am guessing the weight based on the fact that I am in NJ. I figure non-synthetic/synthetic is a bigger issue than the weight of oil I add (.5 to 1 qt.) to top things off.

Thanks!

Post by **JRL** » 07 Jan 2013, 15:28

You need at least a quart anyway so why not change it now and be done with it.
Mobil 1 not MobilE 1

slione · Post by **slione** » 07 Jan 2013, 15:36

JRL wrote:You need at least a quart anyway so why not change it now and be done with it.E 1

I know... Just don't have a free weekend for a couple weeks or more. I'd prefer to just top off but if that is a bad idea I'll have to make the time sooner than later. The hoildays were a bit more costly than expected so I'd rather do the oil myself than have it done.

JRL wrote:Mobil 1 not MobilE 1

Doh! Thanks.

slione · Post by **slione** » 08 Jan 2013, 17:05

Found an answer to my question#2 here (new site to me): http://www.bobistheoilguy.com/forums...ue#Post2242337. In short, mixing synthetic and regular oil is nto a big deal so long as the weight is the same.

I'm adding this should BobTheOilGuy.com forum be helpful to others that come across this thread in a search.

ChaddGostas · Post by **ChaddGostas** » 08 Jan 2013, 19:26

ok, the smoke coming out of your dipstick? is the car running or turned off.
the oil leak could be coming from the top of your engine.
Remove the spark plug cover and see if there is a pool on the top?
My car goes through about a quart every 300 miles.
I put Bardahl in my motor on two engine changes and haven't used a quart of oil in 3000 miles now
I think my valve stem seals are the problem.
your vehicle sounds as if it is doing the same thing.
Look for your oil leak running down the back side of the engine, right side, <distributor side> right above the exhaust manifold. There is a little plastic dam piece that allows oil to weep through.
Is there oil on the top of the spark plug cover? replace the oil filler cap seal. That was a huge loss of oil on my engine.
Chadd

slione · Post by **slione** » 08 Jan 2013, 21:36

Thank you Chadd! I will take a look and see if I can determine the source. There is no smoke out of the dipstick - only the filler. It is evident when the engine is hot but off and I open the filler.

Japedo · Post by **Japedo** » 09 Jan 2013, 05:41

With the engine running. Remove the dipstick a few inches, check for smoke coming out the dipstick housing.
With the engine still running, remove the filler cap, check for smoke coming out there.

Checking for smoke in these areas with the engine turned off isnt going to determine anything.

Hope this helps

slione · Post by **slione** » 09 Jan 2013, 14:40

Japedo wrote:With the engine running. Remove the dipstick a few inches, check for smoke coming out the dipstick housing.
With the engine still running, remove the filler cap, check for smoke coming out there.

Checking for smoke in these areas with the engine turned off isnt going to determine anything.

Hope this helps

I ran this with the engine running and no smoke was present at the dipstick or filler cap. Therefore, does this rule out the PCV as the cause of my oil loss? There is no blue smoke when starting, driving or accelerating coming out of the exhaust so I don't think I am burning oil.

I'll follow the advice from Chadd and check for top of engine leaks and see what I find.

In the classic Beetle circles the saying goes... "Beetles don't leak oil, they mark their territory." I guess my Bug and XC70 are competing for alpha dog of the driveway.

Japedo · Post by **Japedo** » 09 Jan 2013, 15:22

Yes! The fact that you are not seeing smoke in these areas indicates your pcv isnt plugged with carbon

A further bit of testing to completley rule out pcv, with engine running remove oil cap and stretch a rubber glove over the filler hole. At idle a properly ventilated engine makes vaccuum pressure and will suck the glove in, demonstrating that it has vaccuum at idle.
If the pcv is plugged it will inflate the glove somewhat like a balloon.

Since u have no visual smoking im 95percent sure you will not see the glove inflate. Im thinking your pcv system is fine.

As far as your oil leak goes, i would have to look it over to figure out where its coming from.

Hope this helps!

slione · Post by **slione** » 10 Jan 2013, 05:43

Japedo wrote:...with engine running remove oil cap and stretch a rubber glove over the filler hole. At idle a properly ventilated engine makes vacuum pressure and will suck the glove in, demonstrating that it has vacuum at idle.
If the pcv is plugged it will inflate the glove somewhat like a balloon.

Thank you Japedo! This is a great tip.

I did not have a rubber glove but did the test with a thin, fold-over-type plastic sandwich bag. There was definitely vacuum, although not strong. Is the vacuum supposed to be slight? If it should be stronger then I am thinking either the PCV is on its way to getting clogged and needs to be watched or perhaps there is a gasket or some other leak someplace (and perhaps the source of the oil loss).

Steven