Date: Fri, 24 Feb 2012 13:18:18 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Diagnosing temp rise issue
In-Reply-To: <CAK-ud2hT1d5NUzVMVq4G_Rr8ab3nWVmuVZR-NWPfkNna8Gy7jw@mail.gmail.com>
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Normally the gauge should ride middle to just above the LED. You may have a
bad or incorrect thermostat. The Vanagon has so much cooling capacity that
any thermostat leakage can cause this effect. Also for winter make sure that
bypass valve on the thermostat housing is closed. If the engine had any past
water pump bearing failures the impeller can crash into the case making a
real nasty groove on the case face. This will reduce pump performance at low
speeds. The radiator can also get gunked up or an internal crack will cause
a flow restriction or the coolant to enter-leave the radiator without
actually flowing through it and getting cooled. If you remove both hoses you
can look up the tubes and often you will see the crack. You can also see
there is a mess inside that says time to replace it.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Gregg Carlen
Sent: Friday, February 24, 2012 12:26 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Diagnosing temp rise issue
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).
