John Rudolph wrote:
>
> Thanks to Dennis Haynes, Kenneth D. Lewis and Justin Jensen for the great
> advice! I went the VW service place to discuss your suggestions and after
> further discussion I discovered that neither of the mechanics have
> actually had to do a major repair on a Vanagon AC system. I am going to
> meet the mechanic and an outside AC guy this morning to try and solve
> this thing. The noise in the system seems to be coming from up front so I
> would like start our search there. Problem is, my mechanical crew seem
> quite gung ho to rip out the evaporator and expansion valve and then
> progress to the air dryer but I would be more inclined to have a look up
> front. I am thinking that it might be a good Idea to bypass these systems
> one at a time till we find the culprit. Any Ideas??
>
> John Rudolph
> 86 GL Weekender (LIKE NEW NO RUST!!)
> 88 GL Weekender (Plenty of rust)
> 85 SAAB 900 (Like New)
> 89 Dynasty (To drive when European Iron breaks)
John,
Before you get too far into your perceived problem, do two things:

1.  Have your mechanic apply and interpret a manifold gauge set.  This
should show you immediately if you have a system obstruction.

2.  Find another like vehicle and make note of it's a/c operating
noises;  most Vanagons I have come in contact with have what could be
considered a "distinct" noise (vibration) in the front of the vehicle
with the a/c running.  This noise is a result of less than adequate
isolation mountings for the a/c components to include the receiver dryer
and the condenser coil.  The sound is actually the compressor doing it's
job, generating pressure, with the impulses being transmitted to the
vehicle frame.

Good luck.