Sunday, November 26, 2006

VW - Leaky Valve Covers


>My vales covers have started to bleed on me and I'm gonna be replacing the >gaskets here shortly. My question is, what can I do to make sure there won't >be any leakage when I put on the new gaskets? Is there a gasket glue I can >use or something olong those lines, how bout doubling up the gaskets?

With the valve cover perfectly clean, attach the new gasket to the valve cover using any common gasket cement (Permatex, Indian-head, etc).

Do not attempt to use two gaskets. A second gasket will not fit. The system works perfectly well with just one.

There are three principle causes for leaky valve covers, two of which are obvious and one that is not.

The two obvious causes are: (1) Age and heat causing the gasket to become compressed and hard so that it no longer forms a seal, and (2) The gasket gets out of position, either because the gasket is not properly glued to the valve cover, the wrong valve cover is used or casting flash on the head prevents the valve cover from seating properly.

The less obvious reason has to do with the sealing surface around the valve gallery -- the surface against which the gasket is pressed to form the seal. IF this surface becomes scratched or dinged -- even slightly -- it will not form an oil-tight seal. These scratches and dings usually occur when we adjust the valves.

If the sealing surface is not perfectly smooth, make it so, using a mill-cut file and #320 or finer sandpaper.

The edges of this sealing surface should have slight chamfer (1/32" or less).

The typical veeduber ignores this accumulation of tiny scratches and dings because it's 'obvious' such minor things can't cause an oil leak :-)

Properly assembled, the VW engine leaks no more oil than its water-cooled cousins.

-Bob Hoover
-Feb 1999

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