[Vwdiesel] Vacuum Pump

Roger Brown r.c.brown at ieee.org
Mon Sep 26 23:28:43 EDT 2005

David Cook wrote:
> What is the reason to vent the pump to the Valve
> cover?
> I'm having a hard time seeing what you are talking
> about in that picture.  I can see the pump, but only
> see the vac line that runs up to the brake booster.  I
> don't see a T.

With the 1.9 engine, I have no tee at the top, rather tied into the 2-port round breather fitting there, that is the big black 
hose the comes off the valve cover and runs down in front of the block.  In any event there would be a tee fitting down below, 
but again on my 1.9D engine, the rotary pump is not vented to the crankcase.  And sorry, I did not have any photos of the setup 
in my '81/1.6D.

But the idea is to re-plumb the vent lines, VW used to make a kit, but you can DIY.  Get two tee fittings and a length of hose, 
put one tee at the vacuum pump outlet, the other tee at the valve cover-intake vent line then hook the two tees with the new 
hose.  You end up with something like this:

Intake--+--Valve Cover
CrCase -+--VacuumPump

The interconnection of the two lines allows oil fumes and crankcase pressure to be sucked up into the intake, keeping it out of
the pump.  However, if the crankcase pressure is from excessive blowby, this may not fix the problem and new piston rings is the
real fix.  I had the same problem on my old '81 and the new plumbing completely eliminated my vacuum pump failures.


More information about the Vwdiesel mailing list