Burning Oil

[DannyH]

it seems that my baby is burning oil and i suppose i should be thinking about fixing it

i'm told the 2 most common reasons are piston rings and valve stem seals, how can i tell which it is and what other reasons can there be?

i was thinking (in advance) that if a compression test is ok then it would not be the pistons but the seals would that be the case?

[lenny125]

This what I have found on another forum

This applies to Mk1 & Mk2 8V engines though it might apply to others as well. Having owned Roccos for many years I have amassed some useful tips along the way. This one has caused 2 folks I have met, to incorrectly scrap the car in one case & buy a re-con engine in another ! It also happened to me, but another enthusiast (at the breakers, where I was pricing a replacement engine) told me what to check, as follows.

Symptoms are all that you would expect of an engine with worn or damaged, pistons / rings / bores. Oil & oil vapour blowing out of the filler cap, dipstick hole etc. Air filter wet with oily mess. Air filter casing wet with oil. Oil smoke from the exhaust. General oil leaks.

Now I know some of you are thinking yeh yeh, blocked breather - well yes that can cause this but that is so easy to check I won't talk about it (much). This is similar but stranger until you understand it.

To check the breather, you can blow (with your mouth) down the cam cover breather pipe in either direction and no resistance is felt, indicating no blockage.

The 8V motor (most variants) have, inside the cam cover where the breather pipe connects, a "chamber" that has inside it a couple of steel plates with many holes drilled in it.

This, I understand, is an "oil vapour / droplet condenser" system.

What happens is this. Many of the small holes get blocked up with a horrible, fairly hard, oily, carbon like deposit, and though some air can pass down the breather, when this happens, oil droplets can also pass through without being "condensed" and returned to where they came from, and find their way into the air filter unit, and then into the motor.

The cure - Remove the cam cover. Don't bother trying to flush it clean, nothing I tried worked. Either buy a (NEW or you might inherit the same problem !!) cam cover. Or if money is tight, do this ( I did this after advice from my breakers yard friend and it worked a treat )

PLEASE PLEASE be CAREFUL - this involves petrol & fire !!! - do it in a safe place and observe all precautions.

You need about 2 pints of petrol and basically what you do is pour some (half a cup approx) into the above mentioned chamber, and set fire to it !!

You need to keep doing this for quite a few times - PLEASE TAKE CARE - after a good few "top ups" - PLEASE TAKE CARE - the horrible deposits will go a dry grey colour, and can be removed by tapping the chamber with a small hammer - you can tell if it's cooked enough because a grey powder will "rain" out as it is tapped. If it doesn't, then it needs more cooking.

I suppose careful use of an oxy acetylene torch might do the same thing and be safer, but I didn't have one. When it looks nice and dry clean, wash it all to get rid of ALL particles of anything, and re-fit it and with luck your knackered engine will be fine again (unless it DOES have knackered pistons & bores of course !!).

Note - The later cam covers have an oil anti-splash shield type affair, presumably to prevent all this trouble in the first place.

[mark1gls]

When I cleaned my rocker cover breather I put an old bit of hose on the outlet then poured in some GUNK left it for an hour or so to soak then got a hose pipe and flushed it out, lots of crap comes out then wait for it to dry (might take some time at this time of the year)

Might be a bit safer then setting fire to it and it will not take the paint off your rocker cover.

[DannyH]

Excellent stuff guys!

i suppose i should have said that mine's a late model Scala injection (91/92), does anyone know if this applies to it?

certainly some food for thought.

does anyone know if the rubber rocker cover gasket is re usable?

ta again

[MikeH]

You should have no problems re-using the rubber gasket. It's definitely worth cleaning out breathers before doing valve stem seals.

If it's the stem seals, you'll tend to get clouds of smoke on the overrun (normally you pull up to a junction and get smothered in your own reek).

BTW, what oil are you running in it. I know a few people who've had problems with burning oil, then they stopped using Castrol oil and the problem went away - it doesn't seem to agree with older VW engines.

[DannyH]

I'm using 15/40 Magnatec but the problem was there with other oils.

it does often smoke at the lights etc but there seems to be no absolute pattern to it sometimes it goes for weeks without using any?

[MikeH]

I expect it'll depend on how hot it is, how you've been driving it, and the oil level too.

I avoid castrol oil in all of mine though. I use Synta silver or Fuchs semi synth.