Gary A Meek wrote:

>         On my holidays just completed, the consumption increased
> to about 50 miles to the litre. Needless to say,  when checking
> the oil, it has the cleanest oil for a diesel!  The exhaust is sky
> blue and never black.
>
> Gary:

I also have a Vanagon diesel.  My oil consumption just kept getting
slowly worse, until two years ago I rebuilt the engine.  It turns out
that there was almost no measurable wear in the engine, but on three of
the pistons all the ring grooves were lined up.  I was blowing oil by
like crazy.  I could probably have turned the rings & gone another
200,000 Km, but I did a full rebuild.

I suspect that your rings are not rated for turbo diesel use.  The
combustion temperatures are much higher for turbos, and they anneal
rings of a lesser metallurgical composition.  This is specially true in
a van, which works the engine very hard.  I have seen many people use a
non-turbo ring and pay for it.  I would only use the OEM rings ,  I
think they are the most trouble free.  Did you hone the cylinders and
knurl and fit the pistons when you rebuilt it last time?  If not, the
rings may not have seated properly, and you may have piston slap,
especially with oversize rings, which also causes many problems.  I
would always replace the valve guides & seals when doing rings.
Replacing the exhaust valves is also a good idea at this time.

--
Diesel John

'83 Vanagon Diesel GL  'The Smoking Tortoise'
'71 S-Cab 'Ole Blu'
'83 Audi 5000 TD
'84 Audi 5000 Avant
ex '71 Superbeetle
ex '71 Window Van
ex '76 Scirocco
ex '77 & '78 Rabbit Diesel
LiMBO & VW Club member