At 11:51 AM 8/2/2008 -0600, Paul Chubbuck wrote:
>   Do you think the thermostat attached to the rear fins
>is going bad?

Highly unlikely.  It's a little bimetal disk that snaps convex or
concave and it's switching a miniscule load that's still above the
minimum (~20 ma) for contacts self-cleaning.  Rated life probably
around 100,000 cycles at 15 amps.  But if it's making good mechanical
contact to the fin you can test by bridging across it, fan should run
continuously.  If it's still intermittent, then not the thermostat.

>   If so, do you know where I can get a replacement?

Take a look at the Thermodisc 36T series:
<http://www.thermodisc.com/productDetail.asp?ProductID=2>
You can download the catalog section to get the details and then
request a sample if you're bold enough -- there's a request form on
the page.  I can't remember whether it's 140F/125F or 125F/110F -- I
believe the former.

I agree with Neil that loose contact on the fin is much more likely,
but I'm not so sure that thermal paste is a good idea.  Thermal paste
must be applied *extremely* thin if it's not to do more harm than
good, and this application was designed to work fine without it.

Your fan motor itself (if original) is probably worn out regardless
of whether it's causing the intermittent operation.  I suggest
replacing it with a Fridge-Mate fan designed for the purpose -- look
in my messages a few weeks back for a source, and on my website for a
drawing of how to mod the original bracket for the new fan.  Compared
to computer-type box fans it draws less current, moves more air, and
is virtually silent.

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"