Date: Sat, 27 Apr 2013 18:49:33 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: coolant overflow fears and thoughts
In-Reply-To: <CAFNeVpG+QSZJtxH4iJ9-hq8WLwnMZwmj=WVETUM7enj716PLDw@mail.gmail.com>
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Once the system is bled enough to work it should never need bleeding again.
Normal cycling (heating/cooling) will purge any remaining air out. Anytime
it has to be bled or topped off between servicing is an indication something
is wrong. From my experience denial never fixes anything. Multiple failed
hoses are a symptom and I have yet to see a pressure cap fail to open at
some point. Unexplained coolant loss is often the result of the coolant
getting forced unseen while you are driving. This usually happens during
extended highway drives or periods of extended load. The heads are being
lifted off the cylinders or you have cracks and under these pressure
conditions the combustion gases are getting into the cooling system. Most
times the system can take this for some time and even bleed itself out but
too much for too long things go wrong. The worst is when enough gas gets
into the system and the water pump stops pumping. The gauge won't indicate
the lack of flow until thermal cycling gets something to flow, usually
steam. Coolant rising in the recovery tank with air space in the main
pressure tank says head problem all over. Coolant blowing out and both tanks
going empty could be a bad pressure cap not holding pressure at all.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Tom Carchrae
Sent: Saturday, April 27, 2013 11:21 AM
To: vanagon@GERRY.VANAGON.COM
Subject: coolant overflow fears and thoughts
My van has been mostly dormant over the winter - although I have been
driving it every week or two, partly for fun, partly to ward off angry
lifter noises. It seems mostly happy.
But...
I drove for 2 hours on the highway/city traffic yesterday. Van was
generally awesome. I was trying to get somewhere in a hurry, so was perhaps
a little heavy on the gas pedal - not that this helped too much, a racing
van it is not (an 84 - 1.9L). Temps were fine all during the day, (I have
an aftermarket temp gauge, which was stuck at about 190oC for most of the
trip)
When I got home I noticed the overflow tank nearly, well, overflowing. I
thought, well, it is just hot, let it cool, then check it tomorrow. When I
checked the next day, the overflow level was the same (nearly overflowing
out the tiny air hole in the top). The pressurized expansion tank had
perhaps an inch or so of air in the top of it.
I have a theory, yet to be checked, that the overflow to expansion tank tube
has a leak/crack in it. I don't see any leaks, but I wonder if sends
coolant down and, instead of drawing coolant back, it sucks air in
somewhere. Or, rather, that this is happening somewhere on the cooling
system. The pressure tank is holding pressure (it releases it when I
unscrew it), so where else could this happen?
Am I dreaming that a $5 hose could fix my problem? I'll certainly try it as
a solution. Or is this a head gasket job. I had a lot of scares last
summer in that department (on a 4000km trip) with a few coolant pipe
explosions - but these seemed resolved when I switched to a new pressure cap
on the expansion tank. decent mechanic in regina didn't think it was head
gaskets because no overheating.
I should note that before this trip I blew nearly $2k on a mechanic who put
the previous new cap on it - sigh!
So, I'll drain the overflow tank today, bleed the radiator (which I assume
must need bleeding unless my engine is shrinking) and pour it back into the
expansion tank.
Also, how clean should your coolant look? I've done a CO2 sniff test on it,
but it still looks a bit filthy to me. Granted, I did perform two coolant
pipe operations where I 'captured and recycled' the coolant - as you would
on the side of the road.
So yeah, I guess it looks like I need to schedule some time to do my head
gaskets. Or new engine. Or I just keep creeping around and shuffling
fluid/bleeding air.
What would you do? Time is a bit scarce for me at the moment. Never done a
head gasket job - but I have some new fuel lines I'd like to install and why
not take off a few more bolts and change the gaskets, huh?.. :)
Thanks,
Tom