Date:         Fri, 24 Feb 2012 12:26:09 -0500
Reply-To:     Gregg Carlen <gregg.carlen@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Gregg Carlen <gregg.carlen@GMAIL.COM>
Subject:      Diagnosing temp rise issue
Content-Type: text/plain; charset=ISO-8859-1

Hey folks,

After my self-induced challenges with my engine (90 Westy automatic in the
DC area, ~70 deg F outside), I finally have Blueberry back and running. So,
after having heads rebuilt and reinstalled (correctly this time), new
gaskets/seals all around worked on areas, new SS long coolant pipes,
various coolant hoses, thermostat housing and thermostat and pink VW
coolant (bled), I've got a strange symptom that I had actually noticed
before the head leak problem started. While the engine was being worked on,
I took the opportunity to take care of several coolant related issues as
well (see below).

The issue that I observe is an unexpected rise in temp on the engine temp
guage. Upon start-up, everything seems to increase in temp as exected.
After reaching what I believe is operating temp, the needle sits just at
the low side of the LED. It stays there as long as I'm driving.

Once I stop for a few minutes (~3-5), like in typcial DC traffic, the
needle will rise to just above the top of the LED. Once I get driving again
(above about 20mpg and about 2,500 -3,000 rpm, she'll cool down to the
middle or low end of the LED.

Another fact: the PO replaced the fan with a non-Vanagon fan and a
hard-wire on-off switch. I did my observations with the fan manually turned
on all the time (e.g. during stop and go traffic when the temp rises, the
fan is runnning). Also, the PO ran regular non-VW coolant in the van for
years on end.

Given almost all the cooling system has been replaced in the past year, the
only components I see that were in the van before I got it is the radiator,
upper/lower/rear over-transmission coolant hoses and water pump (an older
dead one was in a box in the van, so I assume the one in the engine is not
originall and had been replaced sometime in the past, but unknown when).

I noticed when stopped and the temp rises, by increasing the RPMs for 2-4
minutes, the temp would drop.

My first thought is a failing water pump (no indication of leaks from it
and the belt is new and properly tightened).

Barring a water pump, the radiator is the only other thought I have. Anyway
to prove or disprove these two components? Other things to look at? I have
a heat gun, but haven't taken any measurements yet.

Gregg
90 Westy (Blueberry).