Date: Thu, 22 Apr 2010 17:49:57 -0500
Reply-To: Tom Hargrave <thargrav@HIWAAY.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Hargrave <thargrav@HIWAAY.NET>
Subject: Re: Water Cooler System Design Flaw Workaround?
In-Reply-To: <0a3001cae259$efaf24c0$6401a8c0@PROSPERITY>
Content-Type: text/plain; charset="us-ascii"
Mercedes did just this in their 80's V8 SLs. They ran a small purge line
from on top of the thermostat line over to the surge tank. The solution
works really well.
Tom
www.kegkits.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Scott Daniel - Turbovans
Sent: Thursday, April 22, 2010 3:25 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Water Cooler System Design Flaw Workaround?
re
I'm thinking about replacing the purging screw on the radiator in front with
a Hose nipple and some kind of automatic purging scheme?
I've had a plan in the back of my head for just that , for years. Know
exactly how I'd do it, what parts I'd use, when it would be 'active' etc.
however..
I haven't found it necessary.
I don't find bleeding to be a big ordeal, or something that absolutely has
to be done 105 % thoroughly and correctly every time you open the cooling
system in any way.
Sure...........some bleeding should be done, at the radiator.
And *for sure* if it is ever necessary on a regular basis, something else is
going on, like exhaust gases are sneaking into the coolant at the head or
head gaskets, which is a pretty common failure.
also ....the way it's designed ...
what I have noticed for years and years about german-designed systems, is
that they are deigned to work right when the ARE right ..
and nothing in between.
for example....I see a TDI engine in a Golf car where the poser steering
and water pump are driven by the same v-belt.
PS is not a critical system ....but water pump drive is. You could have
your power steering system leaking badly.....
and be on a trip for from any parts stores, , or not have the funds to deal
with it just then ...
and your car is unusable becuse a non-critical system is out. That's not
very wise design in my opion.
And I see it over and over in german and Vanagon design all the time.
I like what one guy said to explain why it's so hard to replace the
waterpump in a vanagon with the engine in the car ...
he said 'they gave the engineers 30 days to come up with the waterboxer
design."
he's joking of course ...but that kinda fits.
If you are bothered by the radiator bleed screw system ...
what do you think of the completley joke head gasket system ??
here's why I say it's a joke ( never mind that the evidence of what happens
with wbxr head gaskets shows that they are not a super reliable design ) On
'all other cars' .......combustion sealing and coolant sealing are both
addressed by one very well made, flat gasket, that is held down onto the
engiine block by thousands of pounds of force, and the bottom of the head is
flat, and it sits on a flat box.
in the waterboxer .......which is PURELY a converted air-cooled design...
combustion sealing is handled by the metal rings on top of the cyldiner
barrels.....and they sit agains the head...
those metal rings are the only thing that seal combustion into the
combustion chambers. They seem to work 'all right' most of the time ...
'most of the time' ....
and the heads are not held down by a lot of force, just 8 studs per head,
with nuts torqued to 37 ft lbs.
In contrast...on a VW inline four diesel engine ....one nice solid flat
gasket, flat-bottomed head, flat cast block...
after the intial torque of ....around 60 ft lbs ...you turn the bolts a
quarter turn more, then another quarter turn ...
and by the second qtr turn you are pulling on your breaker bar so hard it's
flat scary, like surely something is going to break.
And it's 10 head bolts ...the force on the head gasket has to be thousands
and thousands of lbs of force. It ain't going anywhere baby.
so anyway ...the combustion sealing of waterboxer heads is .......rather
casually done, and based directly on what they did with air-cooled engines.
and if some pressure leaks past those metal rings in an air-cooled ....so
what, it pops a little under load. In a waterboxer when it does that ...
and it does happen fairly commonly ...
exhuast gases displace the coolant in the engine .....and coolant doesn't
ciculate then...
and you get hot engine, cold radiator ....just like the main pipes were
blocked, but that's not it.
so that's the combustion sealing ....really rather weak, but we get by with
it somehow.
now the coolant sealing.
to not have the bottom of the head flat, so there is only one level sealing
surface is really dumb !
and is an example of 'engineering thinking' ...'in theory' it should be
fine. In the real world it is not.
There are countless things designed by engieers that should work just fine
in theory, but don't.
the coolant sealing ..
normally the coolant is sealed where it passes from block to head by a flat
head gasket held down with extreme force.
not in a waterboxer engine.
The heads bottom out on the top of the barrels...
and they are suppossed to fit down far enough to compress the outer rubber
water gaskets 'just the right amount.'
it is not hard for minor vairations in cylinder heads, or how the barrels
fit in the block for that gap to be either too large, or too small, or even
tilted...not right on one end of the head, but right on the other.
The first time I found out from a VW dealer tech that when you run into that
...'you try another head' I was just appalled, since they invented
standarized car parts in about 1925....so any head fits right on any block.
It was big deal, Might have been 1918...they drove 3 Buicks to the New York
World Show or whatever it was, took them all apart, scrambled all the parts,
and assembled the 3 cars and they all worked.
so given that ...if one head fits better than another on waterboxer
heads.....man, is that silly.
That comment from the VW dealer tech was almost 20 years ago. The guy said
'put the bare head on ( with the metal rings in place ) and measure that gap
( where the outer rubber gasket goes ) and if it's too small, "try another
head."
so I do that on every head job. I find them not right now and then. Too
small, and it will pinch the gasket and it will leak before it should , like
not in 6 years, but in 2 years.
Too big a gap...and it won't really seal.
it gets worse.
Say you find the dimension is not correct. And you'd like material macined
off the bottom of the head...say it's too tight on one end, but right on the
other end.....
'the problem there' is ....machine shops surface heads referenced off the
top of the head. they make the bottom of it exactly parrallel to the top of
head. That is not what a waterboxer head needs.
It would need to be machined relative to where the metal rings sit inside
the combustion chambers. Not something regular machine shops are used to,
or can even, do. I had one done by an old air-cooled guy ....but it wasn't
easy.
my point is ....the waterboxer cooling system is 'demanding' let's say.
Not like some old front engine, front radiator say, older toyota pick-up
truck where having it mostly full at all will do the job.
Waterboxer vangons need the entire cooling system to be working quite well.
and compared to the silly head gasket set up ...the bleed screw in the
radiator is no big deal.
it's the nature of having a water-cooled engine in the rear, and radiator
many feet away in the front..........that the system will be less
idiot-proof, or neglect-proof and more demanding. .
I can't even think of another car right now with that layout - rear liquid
cooled engine, front radiator. Oh ...ok...Porsche ..
starting with the Boxster ....that's Porshce's first waterboxer engine...
and they had problems with that engine right away ...oil in the coolant or
something like that.
Those theoretical engineers ....
if I was in charge ...after the engineers designed it to be good enough ...
strong enough , cost-effective enough, etc.....I'd demand they make it 20 %
better yet....because 'theoretically enough' in the real world often does
not cut it really.
And yet ...vanagons are just fantastic vehicles, with their special needs
for sure, but worth it.
and I can change entire engines and not bleed fanatically to the front, and
things are just fine.
and any time much bleeding is needed, something else is likely wrong, and
the mind goes to 'head gaskets' at that point.
The head gaskets are good for about 5 to maybe 8 years max.
the little green o-ring that keeps coolant away from the metal rings at the
top of the barrels...those get hard and cruddy in just a few years
sometimes.. It can't really work that well really long term. But we love 'em
anyway !
and if one is to be bothered by anything in Vanagon waterboxer cooling
systems...
it would be the silly head gasket set up. It 'can't' really work long term.
Getting one of the 3 failure modes is not that uncommon - in the heads/head
gaskets :
It's either external leaks at the rubber outer gasekts,. coolant being used
through the engine, or exhaiut getting into the coolant part of the engine.,
But we do love them anyway, and we manage to live with it. And that's
partially why we all know each other here. If they never needed any work ,
we might not be here together.
From: "Tobias Gogolin" <usertogo@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, April 22, 2010 12:13 AM
Subject: Re: Water Cooler System Design Flaw Workaround?
> Yes, as Industrial designer and even more as just a German I am deeply
> disturbed by the thought that something so imperfect could have gone
> into production...
>
> I'm thinking about replacing the purging screw on the radiator in
> front with a Hose nipple and some kind of automatic purging scheme?
>
>
>
> On Thu, Apr 22, 2010 at 12:03 AM, Tom Hargrave <thargrav@hiwaay.net>
> wrote:
>
>> Tobias,
>>
>> Air in the cooling system will cause problems regardless of the
>> vehicle and air blocking coolant flow, not lack of coolant is what
>> causes most engines to overheat. The water pump can't overcome bubble
>> in the upper radiator hose when you stop and your temperature spikes.
>>
>> But several European cars have what I consider a flaw in the cooling
>> system
>> - the "flaw" is that the designers route the upper radiator hose so
>> high or mount the radiator so low that the system can't self purge.
>> This "flaw"
>> requires you to purge the system after any coolant service. For
>> example, you WILL DESTROY THE ENGINE in some 3 series BMWs if you
>> don't follow the correct bleeding procedure to purge the air bubble
>> out of the upper radiator hose after performing a coolant service.
>> I'm sure the if the vanagon has the same flaw then it has a similar
>> purge procedure and someone else more knowledgeable than me of
>> vanagon cooling systems can give you instructions.
>>
>> No reflection on your abilities but this is a good example of home
>> mechanics or pro mechanics without the right experience doing more
>> harm than good because they know just enough about what they are
>> working on to get into trouble. The mechanic would change the
>> coolant, not properly purge the system and then the mechanic or his
>> customer would pay the consequences later.
>>
>> Tom
>> www.kegkits.com
>>
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On
>> Behalf Of Tobias Gogolin
>> Sent: Wednesday, April 21, 2010 11:56 PM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Water Cooler System Design Flaw Workaround?
>>
>> I suppose most of us are aware that if for whatever reason there is
>> air in the cooling system of a Vanagon (T3?) it will overheat because
>> the system gets 'air locked'. That means the coolant cant flow
>> through the radiator because it would have to push air down in the
>> return path an there is obviously not enough pressure to do that...
>> I'm suspecting there could be some solution, one would be to put the
>> radiator down where the spare tire is and eliminate the potential
>> vapor lock, or... what else ?
>>
>> Thanks!
>>
>> Tobias
>>
>>
>
>
> --
> Tobias Gogolin
> Tel. Movistar (646) 124 32 82
> Tel. Telcel (646) 160 58 99
> skype: moontogo
> messenger: usertogo@hotmail.com
>
> Blog: http://zeitgeistensenada.blogspot.com/
>
> You develop Sustainable Ranch Technology at
> http://tech.groups.yahoo.com/group/SURA-TECH
> an Open Source Electric Motor/Alternator at
> http://groups.yahoo.com/group/Performance_Axial_Flux
> and an Open Source Motor Controller at http://groups.yahoo.com/group/GoBox