Michael, is it knocking ( a deep sound) or is it more a clacking sound
(lighter). Vanagons have what is commonly referred to as the Vanagon
clacking lifter syndrome. Typically it is the result of a lifter losing
its prime and the oil running out  of it. znxt time when you start the
engine, it clatters, because it is out of adjustment due to the
clearance change resulting from the loss of the oil. Running for 1/21
hour or so will pumop it back up. Ways to avoid the problem is to go to
a 20W50 wt oil, and install a Mahle or Mann oil filter - available from
some of our List Vendors like Ken Wilford at Vanagain.Com or Ron Salmon
at The Bus Depot.. These two filters are constructed so that the
internal relief valve spring is sufficiently strong that oil pressure is
retained in the oil galleries after the engine is turned off. Adding  a
can of Marvels Mystery Oil to the crankcase also helps. These solutions
are old standby's gained from the collective experience of the members
of this list. Works most all of the time.

John Rodgers
88 GL driver.

Michel Bertin wrote:

>A few days ago I had my van with 1.9l waterboxer idle for maybe an hour or so everything was running fine when I parked it. Now tonight I started my van after a few days in the garage and it is knocking very bad. It seems like it's coming from around the valve cover.
>
>I did check the oil and it was missing 1Litre which I did add and let the egine run and drove it for about 2 km and still knocking.
>
>Can anyone guide a bit and explain what could have happenned so suddenly.
>
>Thanks,
>
>Michel Bertin
>
>
>