That sounds just perfect for temp.
And the 180 to 150 difference shows the radiator is doing what it should.
And the rad fan coming on at low speed when it should - all sounds normal.

It's the single contact sensor that operates the gauge.
Trying another, or a new,  temp gauge sender seems indicated to me. 
Or put a resistor in series to calibrate your gauge. 
Scott
www.turbovans.com 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
craig cowan
Sent: Friday, July 27, 2007 6:29 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: How Hot is To Hott?

I just tested it with a Temp gun. The pipe going to the radiator (in the
engine bay) is reading a consistant 180-185* with the heaters on (and with
the heaters off it didnt seem to change) yet the temp guage is still clearly
"HOTTTT". The return water from the radiator is about 150* and the fan is
working (at least on low).

I recently replaced both temp sensors, could that be it? TEMP 1 is what
works the guage isnt it?

Any help is appreciated.

-Craig
'85GL