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Subject:Hot Weather Effects... and some information.
From:John Klun
Date:Tue, 10 Jul 2001 09:57:22 -0600

Fellow Listees-

Out here in Delta, CO, in the 'adobe desert', the daytime temperatures can
hit 105+ in direct sun, every day in the summer.  We are in the middle of
this 3 month period.  Our Vanagon and Jetta are parked in direct sun.

I was driving the Van around our field irrigating when I heard the fuel pump
start to buzz.  It buzzed loudly for the remaining time I was out in the
field.  I finished and parked it in its usual spot.  A few hours later, when
the temp dropped down to around 95, I started the Van and no buzz.

Our '86 Jetta GL is somewhat the same.  The fuel pump buzzes in extreme
heat.

The other day, the Jetta wouldn't start.  It turned over but not catch.  I
left it alone for a day.  I went back out to start it and it caught right
away.

I checked with Bob Birkholz, my mechanic, and he said that with today's
gasoline formulations, combined with hot weather and fuel pump pressures,
the cars suffer from 'vapor lock'.  He's also found that when he rebuilds
old Beetle engines he needs to install a fuel pump in the front tank to
provide the pressure to get it to the engine (plus a regulator to reduce it
to the correct pressure in the engine).

We've had many fuel pump failures on our Jetta since 1986 and the 'no start'
mirrored the fuel pump failure.  Of course, I panicked!

The point to this is that severely hot temperatures 100's+ dry, 90's+ humid
will affect the density of gasoline and your fuel pumps.  So be careful.
Every time the fuel pumps failed in our Jetta, the temps were extremely high
for the locale:  108 in Kansas, 102 in Florida, humid high 90's in New
Hampshire.

Thaaaaaat's all volks!

'84 Vanagon GL (Baby)  200,000+ miles?
'86 Jetta GL (300,000+ miles?)
'65 Chev PU  (Big Black) engine burned up (literally)

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