Marvel Mystery Oil is my choice.  I've used many times with good success.  Use a 1 quart bottle, 1/2 in the with the engine oil, do not over fill so some engine oil must be removed or wait until it's down to the lower mark.  The other 1/2 in the gas tank with a full tank of gas.  Drive the vehicle without stressing the engine until the fuel tank is nearly empty.  Drain the oil, change the filter and fill with fresh oil.

On 2011-05-20, at 12:00 AM, Automatic digest processor wrote:

> My ol wasserboxer has its share of lifter noise.  Especially as I
> reach the end of the 3000 mile oil change interval using castrol
> 20w50 and mahle filters.  I was wondering, as I approach the next oil
> change in a few hundred miles, if I might add something to the oil to
> help clean the engine internals a bit without causing trouble.  I've
> heard SeaFoam and Marvel Mystery Oil mentioned on this list in the
> past.  any recommendations?  I'm thinking a one time treatment here.

Cheers,    

Frank Condelli
Almonte, Ontario, Canada
'87 Westy & Lionel Trains (Collection for sale)
Frank Condelli & Associates - Vanagon/Vanagon Westfalia Service in the Ottawa Valley
Vanagon Stainless Steel Exhaust Systems
BusFusion a VW Camper camping event, Almonte, ON, June 09 ~ 12, 2011