lifters/valves, and vaccum pump noise

[Carl DeSousa <desousa@cisco.com>]

This subject has come up before.  If you have a 90 or a 4000 you
probably have a vaccum pump.  When they get loud they make a clakking
sound that is easily mistaken for lifters.  They are expensive to
replace.  A better solution is to have the thing taken apart and
cleaned.  We have had this done once on our 4000Q and it takes care
of the noise.  Apparently they fill up with oil and need to be cleaned
and drained.  Sorry I can't provide more details, I've never actually
done it myself.   We had our lifters replaced too but the clattering
came back 6 months later.  It turned out as long as the car doesn't
sit for extended periods of time, and the oil is kept clean, and
with an Audi oil filter with a check valve, the clattering doesn't
come back.  btw, I hear the vaccum pump costs $700+....

There was talk of running a cleaner through the system but I haven't
heard of any success stories so far.  Using Slick 50 initially made it
better but eventually it just seemed to get worse.

Carl

> From: Eric Glanz - Unix Support <UCSEDG@uwplatt.edu>
> >He says it's usually the vacuum pump - there is a rod inside that
> >wears, and that is what produces the noise.  They don't usually
> >fail he says, but just get louder and louder. 
> Do you happen to know what rod he is talking about?  Is it the rod
> that drives the pump from the cam, or a rod internal to the vacuum pump?