The major benefit is that is short order you put about 50,000 miles or more wear on the bearings and if the engine is full of gunk, you can loosen it and clog the inlet screen for the oil pump. On engines with removable pans, the screen can be cleaned but in the Water Boxer, you are looking at a full rebuild. Also, the solvents can do some damage to the seals. Even just cranking, once the oil film is washed off the bearings, wear will begin. Solvents will also remove the dry lube or boundary lubrication additives that provide lubrication until oil under pressure fills the bearings.

Todays oils have enough detergents and additives that flushes are not required or beneficial. Neither are most additives. Change the oil more often if needed. If there is stuff inside the galleys or corners of the crankcase, so what? Leave it there. If you want to improve lubrication, use better oils, synthetics. As for oil condition, appearance does not really tell you much. Oil analysis is the way go. Oil sampling kits are available at Caterpillar dealers for ~ $15. Often they have the kits on sale for less if you are wiling to go for quantities of 10 or so. The also have coolant test kits. Oil testing will give an idea of oil life and detect even minute amounts of antifreeze getting into the oil.

Dennis

----- Original Message -----
From: mordo
Date: Tuesday, January 9, 2007 3:16 pm
Subject: Flushing the crankcase
To: vanagon@GERRY.VANAGON.COM

> Okay, here's one for eveyone's amusement:
>
> Would there be a benefit to draining the crankcase of oil,
> filling with
> mineral spirits, letting it soak for a few hours, disabling the
> spark and
> then cranking the engine to work it around? Seems to me it could
> help to
> remove some gunk from the case and galleys.
>
> Anyone tried this or something similar?
>
> --
> mordo
> 1990 Carat
>