Date: Thu, 11 Jun 1998 12:37:17 -0400
Reply-To: "Forhan, Thomas" <Thomas.Forhan@MAIL.HOUSE.GOV>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: "Forhan, Thomas" <Thomas.Forhan@MAIL.HOUSE.GOV>
Subject: 91 Overheating: Comparison (long)
My buddy is having problems with his '91 Carat. He says the temp guage
runs up pretty quickly above the little red light, which often starts
flashing. Turning on the rear heater fan always lowers the temperature.
On long runs, climbing long hills, the needle goes way high, and the oil
starts acting like its too thin- the buzzer, the light, etc.
The Carat has 135,000 miles, head job done by prior owner at unknown
mileage. His mechanic seems to be the part switching type, and on three
visits has replaced the coolant, installed a new thermostat and put in a
new radiator fan switch. No significant change. From my own prior
experience, I have little confidence in the mechanic's ability to diagnose
.
I see no evidence of leaky heads or coolant leaking anywhere else either.
We've re-bled the system, and changed the non-standard oil filter to a
Purolator, and the 30W oil to 20W-50. Hoses look ok, although the one
leading down from the expansion tank is more flexible and has a bit more of
a turn -a proto kink, if you will- than the one on my van. Water pump is
not leaking.
After extensive search of the archives, and because the rear heater helped
the situation, I was thinking it's a radiator problem.
So last night he parked his Carat in my driveway, next to my 90 Syncro
Westie which seems to run nice and cool: temp gauge never goes beyond the
little red light (except once climbing out of Death Valley in August). This
morning air temp was about 60 F. We took the grills and engine covers off,
and started the engines up at the same time, letting them sit at idle. Both
cars have a/c., so it is impossible to put your hands directly on the
radiator fins to check for even coolant flow, though you can feel the
"before" and "after" header tanks (if that is the correct name).
After several minutes at idle, both vans' temp gauges came off the pegs
pretty much at the same time. Another few minutes and the thermostats must
have opened up, because both the right hand tanks on the radiators started
getting warm, and a bit after that both the down stream sides started to
warm up. Temperature increases wherever we could touch the radiators were
pretty much the same. It seemed to me that coolant flow in both buses was
similar- if this sort of experiment has any validity. Up to this time, both
vans behaved the same.
But from then on, his van kept on getting hotter. My gauge stopped a tad
below mid-light, his gradually climbed up and his first level fan came on.
It kept climbing to about half way between the light and the top, when I
turned on the rear heater and temps dropped down almost to the top of the
light.
All this was done at idle speeds only. At this point it was time to go to
work so we did not push his to the top. I never did see his coolant light
flash, though.
Hints? Suggestions? Comments?
Thanks,
Tom F.
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