[Vwdiesel] 9k rebuilt '82 Diesel Westy coolant temp rising, but better at high revs?! Air bubbles but no gasket issues??

[James Hansen]

Will
Sucks to work on coolant in the great outdoors, particularly winter
outdoors, something to be said for an aircooled.
Definitive test would be to bypass all the stuff, and run hoses that go to
and from rad into a bucket so you can see the flow, or lack thereof.  Yeah,
like you want to try that in winter...

Just a side note, you can't have an air leak in a pressurised system,
period, they just don't work properly at atmospheric pressure. Your leaky
line will leak coolant out, and air back in when shut off and things
contract completely screwing up the works.  I haven't met a vw that
tolerated any air in the system, and unless you park your westy on a teeter
totter for the night, air is even more of an issue in them.

Impeller can't fall off a little bit.  When it fails, you get zero flow,
period, and hot hot don't drive anywhere kind of conditions, coasting down a
hill won't help you a tiny bit then, kind of like a plugged rad hose like
you forgot to take a plug out of a rad hose on reassembly kind of plugged.
(how do I know that you ask, heh heh.)

Plugged exhaust can do it too, but I would suspect the thermostat.  Utterly
failed thermostat does not flow correctly- the vw system depends on it being
there, and working.  The thermostat essentially is a switch, to run two
different coolant paths, not like a chevy where it just turns coolant flow
on or off. Stuck shut, you only get circulation to head in a loop, not
including the rad or block.  Stuck partially open, you get good flow
nowhere- and it should heat up the hoses, but not hot.  Remember now, I know
diddly about the westy coolant path, but this applies to the cars.  From
what I know, the westy is similar at the engine, just has really, really
long rad hoses that should have been made of stainless to reach the front.
Good luck Will, hope you find it.
-james



-----Original Message-----
From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com] On
Behalf Of Will Taygan
Sent: November-28-11 12:52 PM
To: vwdiesel at vwfans.com
Subject: [Vwdiesel] 9k rebuilt '82 Diesel Westy coolant temp rising, but
better at high revs?! Air bubbles but no gasket issues??

'82 Westy #2 has always had some bubbles in the coolant reservoir.  9000
miles on rebuilt 1.6NA.  

**Now it's "overheating" UNLESS I drive at high rpms.**

(Just getting 1/2 way to the red light, but I'm actively trying to keep
it low.  Idling down long downhills also drop the temps?!)

I do have a weepy return coolant pipe/hose connection in the engine
compartment.  No pressurization of the system - in fact I've used 4
different pressure caps and none push or suck into the overflow
reservoir!  Also no sign of exhaust gases in the pressure tank,
according to one of those diesel exhaust gas tester things.

Coolant pipe to radiator is warm, return pipe is cold, although the
return hose is warm (probably heat from the bottom of the coolant
reservoir??)

So...  

Bad water pump?  This is my first guess, But perhaps not because high
revs cool the system?  I can also see good? flow in the pressure tank.
Maybe a loose impeller! (it's the plastic/cast metal combo kind, yeah -
tell me where to get a better one!  Stamped??)

Bad thermostat?  Perhaps not because the outgoing coolant pipe is warm,
and things do cool off at high revs?

Clogged Radiator, Hmmm..  this seems like a possibility as well??  The
van did sit for 3 years, I cleaned the pipes and radiator, but there
could easily be residual gunk.

Air in the system?  Yes, this is how my head-gasket usually blow, or how
air works it's way out of the system, but only source I can find is the
weepy pipe/hose connection, maybe making itself into a one-way valve??
No signs of actual head gasket failure.

Bad injector spray pattern?  Well, they've only got 9000 miles on them.

Clogged air filter - 9000 miles?  I guess I'll replace it just in case?

Clogged Exhaust? - Dunno.  But high revs fix the problem?

It's COLD outside and I'm working in the snow, the prospect of working
on the cooling system is not a happy one.

Ideas?  Opinions?  What am I missing? I do have a '85 radiator and hoses
sitting in the parts pile, but...

Thanks,

Will in Alaska.

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