Why did you think you needed to change the sensor in the first place? An
which coolant temp sensor? The one for the gauge or the ECU? If the sensor
is leaking it will be obvious. If you changed it to solve an overheating
issue, most likely something else is wrong. Unexplained coolant loss could
be internal, one of the heater cores etc. It could also be a sign the system
is not properly filled and bled and the system is trying to take on the
coolant.

Is the low coolant indicator working? If the system is not properly filled
and bled you cannot rely on the temp gauge as the sender requires properly
flowing coolant to work. That is why there is the low coolant level sensor
system.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Bill Burnham
Sent: Wednesday, June 13, 2012 9:08 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Coolant temperature sensor

Hey all, first time post, but I'm feeling squirrely about a minor fix that
seems to have gone bad.

I have a 1991 Vanagon. Yesterday I replaced my coolant temp sensor (engine
part, not the one that is in the coolant tank) and now I'm experiencing a
steady drop in coolant level. The expansion tank dropped to nothing
overnight after the fix. I filled it this morning at 9 a.m. and it was
depleted by noon. I refilled it around 3 p.m., took an hour drive, and by 7
p.m. it was below the mark and dropping. I'm sure it will be empty by
morning.

Clearly there is a leak somewhere in the system but I've put the van over a
pad and I don't see it pouring out. Where is this liquid going?

I did include the O ring when I put the new sensor in, but given the loss of
coolant, either I didn't install it right or there is a bigger issue.

Any ideas/thoughts/input are appreciated.

Bill in VA

1991 Vanagon

Bill Burnham

Onancock, VA

305-240-3298

757-787-2933

www.southeastexpeditions.net

www.burnhamguides.com