The water in the pump return pipe is the mixed coolant return water. In
other words it is the water that is cooled by the radiator. The original
gauge sender location is where the coolant exits the engine.

Yes the oil will get hotter than the return coolant temperature. The oil
cooler uses the hotter discharge coolant for cooling the oil(???). In
addition high speed and load can get the oil even hotter. With some effort
the oil can make it to 280 or more. This is the real Achilles heel of the
Vanagon engine. This is when oil pressure problems can develop and the
thrown rods and broken rod bolts really begin.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Max Wellhouse
Sent: Saturday, September 19, 2009 12:35 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Water Temp sender location

Some time ago I had a wheel bolt welded to my metal pipe that bolts
to the water pump with the thought athat some day i'd find a 14x1.5
VDO sending unit for my on top of dash VDO temp gauge.  Now that I've
found a sending unit and it's arrived, I screwed it in last night

The question is; I this an optimal place to measure water temp?  The
factory chose up by the thermostat for their gauge, and I'm noticing
that the oil temp(unit down where the oil filler tube used to be a la
Ken Lewis design) reads higher than the coolant temp.  How does the
oil get hotter than the coolant or is the metal pipe area the coldest
the coolant gets?  I would think being that close to the exhaust and
all that it should read hotter than the oil at least until 15' or so
of highway driving.  Yes, I have a 150C gauge and the complimentary
150C sender, so it's not a mismatch of resistance or whatever.  I
will ocntinue to play with it some more and observe and report back.

Inquiring minds wanna know.

DM&FS