Hi ezr!

Good question ... I have heard there is some leakage if the valve doesn't close fully, but don't really know much more than that ...

Would be nice to get a clear answer if anyone has investigated!

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg