Followup:
After about 1500 miles (perhaps 700 of which I had the AC on), my
r134a conversion is still blowing cold, and the compressor noise
seems to have reduced a bit.  Not sure if this is due to it grinding
itself apart, or perhaps the oil has finally squooshed around evenly
and it's breaking in?

On Aug 3, 2006, at 9:14 AM, Michael Diehr wrote:

> My 85 westy has a slow leak (as many do) and so about 3 years after
> my last R12 chargeup, I decided to go for a R134a conversion.   The
> shop (Harris Radiator near San Diego) did a great job, and even
> offered me a guarantee, offering to change back to R12 if I wasn't
> happy with it.
>
> Performance-wise, it's decent and I think livable.  Not ice-cold, but
> quite cool, and I like the idea of not leaking freon, so I think I'll
> stick with it.
>
> The only problem that I've noticed is that when running the AC at
> high engine rpm (3000 ish) the compressor is making a "hum" sound.
> Loud enough to be heard over engine & road noise on the freeway.   I
> can't remember if it made that sound while running on R12, since it's
> been a while, but I don't think so.
>
> Is it possible that R134 is putting more stress on my compressor and
> hence the noise?  If so, is this the sound of progress or incipient
> failure?