Date: Mon, 31 Jul 1995 20:14:42 -0400
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: BBTSQP8@BAPLAZA.BELL-ATL.COM
Subject: Re: external cooler/filter : trust the dipstick?
Hello again all-
I was helping a friend with his bus the other day, and I got to
thinking about something: He has an external cooler and a filter, of
the "replace-the-stock-cooler" variety, and he has it all mounted in
the engine compartment. I know he's preheating his cylinder-cooling
air that way, but that's not my question this time. What I'm
wondering is:
With all that hose and cooler and filter up above the case, it seems
to me that perhaps you can't trust the dipstick any more. Would the
extra oil from the cooler/filter/hoses drain back down into the case
and make it appear over-filled when it's really OK?
Hmmm,
-Mitch
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Mitch:
I would go with the dipstick. The filter is probably mounted in an upright
position, which means that it should retain its oil. The oil cooler will drain
back into the case, but so would the stock one. Sure, there is some extra volume
due to the length of the hose and the larger capacity of the cooler, but not too
much.
There are some things I would be concerned about. First, if you were to overfill
the oil, the cam and crank counterweights could whip the oil into an aerated
froth, possibly causing low oil pressure and bearing damage. Second, if you were
to underfill it, with the extra capacity of the cooler and filter, the engine
could possibly experience low oil levels in the sump, and low oil pressure
during acceleration, cornering etc. Kinda damned if you do, damned if you don't.
Trick is to find that happy medium.
My suggestion would be to install a thin-line oil sump and oil pressure gauge.
The thin line sump would allow you to fill the oil to the "normal" spot on the
dipstick, and not worry about frothing. Also, it would more than compensate for
the greater fluctuation in oil levels that could occur due to the increased
capacity of the pressurized side of the oiling system. This is because the oil
pickup tube sits about 1.5 inches lower in the sump. The pressure gauge--just
for good measure.
On my '65, I installed the thin-line sump, and it ended all of the low oil
pressure problems I experinced during spirited cornering, on-ramps, etc. I am
completely satisfied with the results.
Any comments on my theories? I would love to hear them.
Tom Carrington
BBTSQP8@bell-atl.com
88 Vanagon
65 Notchback
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