Date: Wed, 30 Mar 2016 11:39:00 -1000
Reply-To: "SDF ( aka ;jim lahey' - Scott )" <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "SDF ( aka ;jim lahey' - Scott )" <scottdaniel@TURBOVANS.COM>
Subject: Re: Coolant Loss- is it that time again?
In-Reply-To: <CAGbP_PiQ+We77v0kC7K=etNj48szCQaOYqiwQRW6oJ8p9n7zJA@mail.gmail.com>
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I divide all forms of 'lost or consumption of coolant' into two broad
catagories..
External leakage
or
Internal consumption.
A pressure tester helps to locate external leaks.
Sometimes they can be really small and hard to find.
Sometimes there will be an external leak that leaks onto a hot surface,
and therefore will not result in a spot on the ground under the van.
Ideally, with a pressure tester you can pressure up the system and see
how long it holds pressure.
Should hold for quite a while. ...hours even.
since it's roughly a 14psi system I don't pressure much over that.
The 'outer rubber water gaskets' like to seep and leak of course..
very weak semi-joke design. NO other car uses that
adapted-air-cooled-design system.
I've seen those rubber gaskets split from being too tightly compressed.
I've seen the sealant not work for a long time becuase the gasket was
not compressed enough.
I have seen a head sit on the barrels tilted, so it's too small a gap on
one end, and too large a gap on the other end. Totally a joke...it's
amazing how well they do work sometimes.
if you're convinced it's not some external leak ..
then you start thinking about coolant consumption within the engine.
sometimes you can smell a-frz in the exhaust .
Reading exhaust header pipe temps with an IR temp gun might reveal
something ..
or draw attention to one side or cylinder.
Sometimes visual inspection of spark plugs could reveal something.
a Most Tricky situation is exhaust gases getting into the coolant at the
heads.
When it's significant, it's easy to spot ...you have extra hot engine,
and cold radiator.
if it's minor or intermittant ..harder to determine.
a Leak Down Test can sometimes show something.
Generally ..on all engines ..if it's not a thermostat issue, or an
external leaking issue, or a tired radiator,
and there are no external leaks ..
you start thinking about removing the heads.
11 years is about right anyway. lol.
a gallon is a lot to add !
Surely something will show up to match that sympton.
re bleeding and air in heater cores ..
generally ..'even on' 1.9's with there 'why didn't we make this better
in the first place' cooling system ...not a problem.
All I usually do is top of the pressure bottle after every warm-up/cool
down cycle until it won't take more.
Naturally ..the front heater valve should be on during the
filling/warming up process.
Like look for good defroster heat after a few minutes of running.
I find that it takes some rpm, say 2,500, to initially get coolant
flowing in the front heater.
if you still have metal T's in the heater hoses back there for the rear
heater..
those like to rot and rust very nicely. Easy to have a small leak there.
you can get a good idea on the amount of corrosion in the coolint system
on any aluminum hose nipple ..say the hose going forward on the right
head ...you find it's all pitted there ...even turning to aluminum
powder sometimes under the hose ...not a good sigh !
In every aspect, corrosion is the main enemy of all mechanisms,
suspension, electrics etc.
When I worked on jet interceptor aircraft avionics systems in the AF
long ago, we had a whole shop and department Just For Corrosion Control.
let us know what you find !
scott
On 3/30/2016 4:02 AM, David wrote:
> On my 85 1.9 (second set of heads...that we did 11 years ago) I'm
> suspecting internal leakage...
>
> I have had a lot of coolant loss over a long period of time...I topped up
> the bottle- thinkng that maybe when a heater control switch was switched
> out that we just didn't get all the air out of the system...
>
> I did have another external leak that I fixed- but something just doesn't
> seem right.
>
> Just finished pouring about a gallon of antifreeze into the system this AM-
> and doing some bleeding...what's next? How can I locate this internal leak?
> Or would there be some other not so obvious places? Rear heater is
> bypassed...maybe lost coolant from that operation and it's only showing up
> now...something aint right!
>
> The engine runs like a champ- full power - after my more recent electrical
> (I believe to have been) issues- reseating all major suspects...it runs and
> idles wonderfully....
>
> Any advice is welcome... do we have to check for exhaust in the coolant?
>
> Dave
> 85 1.9 GL MT
>
