Dave Plowman (News) wrote:
In article ,
Bill wrote:
I have always wondered whether this is a standard get-rid-of-him phrase
taught as part of the Car Mechanics PhD (Hons) course, or whether alloy
does actually start to leak.

Just the usual meja ********. If alloy really did go porous, your engine
would soon be scrap. Given pistons are made of alloy and have been for
many a year as is much else on a modern engine. And the pressure inside a
cylinder is far higher than in a tyre.

If a steel wheel is rusty where the tyre meets it, that will leak too.


ISTR way back when I was a lad, that some Norton crankcases were found
to be porous. They had to paint the inside with something-or-other to
stop them leaking.