Date: Sat, 30 Jan 1999 03:37:18 -0600
Reply-To: Budd Premack <bpremack@WAVETECH.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Budd Premack <bpremack@WAVETECH.NET>
Subject: Simplified Coolant Leak/Air Bleeding Technique
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Jim Fritz wrote about some coolant seepage from his Westy while in winter
storage. It has about 150 lb compression in all cylinders and does not seem
to show any head gasket leakage. He wondered about a leaky hose. My
response is as follows.
I am so far from Master Mechanic that I barely have my Novice Certification.
However, I do read and listen well to those who are knowledgeable. It would
seem likely to me that a leaky hose could easily seep coolant under storage
conditions. Since the van apparently hasn't gone anywhere, it should be
relatively easy to visually trace the drops of coolant. Just use a trouble
light, and hope that your eyesight is better than mine is.
If you don't find anything, you can add some pressure to the cooling system
by using Darrell Boehler's technique. Remove the 1/2 inch (approximately)
hose on the pressure cap at the top of the expansion tank (driver's side)
that connects it to the fill tank (behind the license plate). Get a bike
pump and some plastic hose of appropriate diameter so that the pump can be
connected to the expansion tank. You may need to use a couple of different
diameters of plastic hose to step up or step down from the bike pump to the
intake on the expansion tank. These hoses can be purchased for pennies at
any hardware store. Make one of the hoses long enough so that you can hold
the bike pump easily. You are not dealing with high pressure, so friction
fit will be adequate; small hose clamps are not necessary.
Pump the bike pump a few strokes, remembering that the normal cooling system
pressure is around 15 psi, not the 50-80 psi that bike tires take. This
pressurizing of the cooling system will encourage any leaks to become more
obvious. Find them and fix as required. The tremendous advantage of this
procedure is that the motor is not running and everything can be checked
without any concern for burning yourself or getting tangled up in the moving
belts.
This technique also works wonderfully well for bleeding air out of the
system, which can occur if the coolant level got too low or for many other
causes. It is also necessary to bleed the system when you are doing your
annual coolant change.
You will need to raise the front of the van about a foot, so that the
radiator is clearly the highest point on the system. (Use ramps and/or a
sloping parking space.) Pressurize the system with the bike pump. It seems
to me that waiting a bit at this point would allow the air to congregate at
the top of the radiator (but remember that I am only a Novice Mechanic).
Then open the radiator bleeder screw (easily accessible once you remove the
top front plastic grill) a few turns until all of the air has escaped and
coolant begins to run out. This may take a few attempts, as the escaping
air will cause a corresponding drop in the coolant level in the expansion
tank. If the coolant drops too much, you will allow air back into the
system. Even if you do not introduce any air into the system, the pressure
will be reduced as the air/coolant escapes through the bleeder valve, thus
necessitating a few more strokes on the bike pump.in order to keep up the
initial pressure. Be sure to top up the expansion tank prior to each
pressurization. This is done by removing the pressure cap on the top of the
fill tank, topping it up with a 50/50 mix of phosphate-free anti-freeze and
distilled/de-ionized water, and then replacing the pressure cap. At this
point you will need to pump up the system again, but this only takes a few
strokes on the bike pump.
Once the air has been bled (apparently completely), close the radiator
bleeder valve, make sure the expansion tank is topped up, remove the bike
pump and replace it with the original connecting hose to the fill tank. Add
coolant mix to the fill tank as required, and drive away with a smile.
Don't be too smug until you have checked the fill tank frequently for a few
days, adding coolant mix as necessary. It is likely that a little remaining
air will find its way out of the system through the normal expansion and
contraction cycles of engine operation.
Now you can look like the proverbial Cheshire Cat as you think of
alternative uses for those many pages in the Bentley manual that call for
the complex Factory Method of bleeding the cooling system. This bike pump
technique can easily be done by one person (even a Pre-Novice Mechanic),
without ever having to start the engine. (Many thanks to Darrell Boehler
for passing on this technique.)
Budd Premack
86 Syncro, 84 GL, 73 Super
Minneapolis, MN (Land of Frozen Waters)
