Today I put all the fluids back in their places (ie, emptied overflow tank,
re-bled system) and for curiosity, I took off the small hose between the
expansion tank and the overflow tank.  It happened to be the same size as
the hose I use to bottle beer, so I stole a bit and replaced it - a
temporary fix, I will replace with proper heater hose.

The old hose definitely had holes in it; I tested by partially submersing
it in water.  The new hose is airtight - and clear - and I saw how it
sucked fluid up from the overflow tank when the engine started.  I don't
know if the hose was original, but it was certainly well worn.

I'm still cautiously optimistic about my heads, will have to see how this
holds up on a longer drive, but that will have to wait for a few days (I
live on a 5km wide Island with a 40km speed limit).

On Sun, Apr 28, 2013 at 7:55 AM, Tom Carchrae <tom@carchrae.net> wrote:

> @Bill - I've blown through that pipe, it is not blocked.  In fact, I used
> it to drain the extra coolant out of the bottle.  I wonder about it being
> air tight though, although I've seen no leaks.
>
> @Dennis - Thanks.  I've been tempted to build a cap tester just to confirm
> my theory on that cap holding too much pressure.  I ended up replacing
> bleeder valve assembly, radiator, and at least one hose after that had
> happened.  The only other thing I can think of that may have caused the
> pressure problems was a badly routed front heater bypass job (the heater
> hose may have been pinched behind spare tire).
>
> I have done the combustion gas sniffer test, and it came out ok.  I guess
> I should have a compression and/or leakdown test done again and see if that
> shows any signs.  As you alluded, I suspect it may only be failing when
> driving/under load.
>
> Any other ideas to confirm the issue before tearing the engine apart or
> replacing... :/
>
> Tom
>
>
>
>
>
> On Sat, Apr 27, 2013 at 3:49 PM, Dennis Haynes <d23haynes57@hotmail.com>wrote:
>
>> 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
>>
>
>