Maybe there is a similarity to the function of the secondary pump to the
one that is used by the 1.6 td.
There is a secondary cooling pump with the 1.6td. This pump, as far as I
have experienced, is only activated when the cooling temp is dangerously
overheated and will remain on even after the engine is turned off. It
circulates the cooling liquid around the oil cooler (an extra
circulation  aid for extreme needs) Also connected to same temp. sensor
is an air blower (fan) which blows cool air to the turbo by way off a
funnel. Both this fan and the secondary cooling pump are only activated
when the cooling temp reaches dangerously close to redline or if you
disconnect the wire from the temp sensor and earth it.

My engine has sort of survived three redline overheating episodes and
maybe these items contributed to that. A working secondary pump is not
at all necessary to the normal running of the 1.6td. You do not say if
your pump is working or not.
Many Audi and VW parts are interchangeable and carry the same part nr.
so there is no inconvenience to be stuck with an Audi part.

After all that, the part nr, is not visible on my secondary pump. If
your pump is working why not use it?. If it is not rusted internally
these pumps easily live a long live and its operation can be checked by
occasional earthing of the temp. sensor wire.

Best regards,  Martin Kennelly

> Specifically, it is a SECONDARY COOLANT PUMP, used to prevent overheating on tubrocharged motors
> after the engine is turned off -- and it is visually the same as those used on Audi 5-cylinder turbos. I am
> assuming that it is a fairly common part used in various Audis and VWs.
>
> So, anyone out there know the part number?
> Is there a VW equivalent?
> or am I "stuck" with Audi-only parts?