rings or valve stem oil seals

when driving the car it doesnt seem to smoke but when ive been stood at traffic lights or when reversing up onto my drive the car seems to smoke a bit its blue smoke not normal white smoke, has anyone any ideas ? the speedo says 86k but not sure if thats the right reading or not.

…suspect the valve seals……our Clipper did that, and had a strange smell too….can't find the receipt at the mo, but it was not too much…..more than worth having it done. Ours were brittle and fell apart……

Yo Shagman

Posted a reply to this on the old web site but yertiz again.

Get a Mate and a long down hill.

Drive to the top of the hill and back down it at a reasonable speed on a trailing throttle (ie take yer foot off the loud pedal).  At the bottom of the hill floor said pedal and get yer mate to check if little or lots of blue smoke is coming out of your exhaust pipe.  If so, tis your valve stem oil seals.

Logic:
When its rotating, your engine needs air (& a bit of fuel).  It will get the air from the throttle body through the open throttle butterflies.  If the throttle is closed, it still needs air (pistons going down creates a vacuum in the cylinders) …more air if its fairly revving as in going down hill.  So it gets the air from wherever it can. Now a suitable place to get air from is from under the cam cover if the seal are kernackered. In fact its nearly the only place it can get air from.  Now the stuff under the cam cover is not just air, its an oily mist from all that oil that is lubricationg your camshafts, springs, tappet buckets et al.  So what is going down your valve guides is all this oily mist since the seals are no longer sealing.  All of this crud then builds up to some extent in your cylinders and when you open up the throttles at the bottom of the hill, it all gets burnt with the fuel/air mix that you now are adding to the mix…and setting fire to it all….and the air turns blue…………

There is a VW "leakdown" test (at least there was in the US!) where the cylinders are pressurised, in turn to see how long the pressure is held.

Supposedly with the right tools, it is possible to change the seals without removing the head.  At our GTIs age though, I would be removing the head, decoking and reseating the valves at the same time.  When fitting, the seals need protection from burrs on the valve stems using the little caps provided in the decoke set.  There is also a little plazzy special tool for fitting the seals also but I've lost mine (looks like a mushroom).



If the air behind you is blue all the time, then its your rings…and the air really will turn blue…

Cheers

My mechanic gave me a quote of about ?120 for the stem seals…they are still on the list of things to do though!!

Dan

thanks guys i thought it was the stem oil seals but just needed the second opinion, yes i do get that horrible oil burning smell its even worse with the roof down.
i used a semi synthetic oil on the last change and thought it might be a bit thin hence the burning oil smell.