I'm thinking out a method of replenishing the antifreeze without any chance
of introducing air.  I seem to waste a lot of coolant by adding into the
expansion tank while the engine is running etc.  Any fluctuation in RPM makes
the fluid go all over the place, and trying to get the cap on at just the
right moment is tough to do without introducing air.  Here is my intended
method; (1) Make temp filler cap from spare pressure cap by removing valvery.
Install this on expansion tank. Attach length of clear tubing to temp filler
cap and the other end into container of undiluted antifreeze suspended from
ceiling or step ladder as high as practical above van. Start siphon by
draining off some old coolant. Clamp off tubing. (2) incline van (3) drain &
flush using tee in heater hose method - mine is brass (4) remove bleeder
screw in radiator (5) fill system with pure water through flushing tee at low
steady pressure, allowing stream to flow from bleeder. While this is going
on, run van for few minutes at 2000 RPM with heater open to circulate water &
get rid of any air (6) Shut off van, water, cap tee, close bleeder screw. (7)
Unclamp tubing (8) Now you have an air-free cooling system of pure water. All
that remains to be done is to remove bleeder screw, which will start to
siphon in pure antifreeze. As each unit of antifreeze siphons in, a unit of
water will be displaced by it and run out of radiator bleeder. Continue until
mixture is correct proportions. (9) install bleeder screw and pressure cap.
(10) Take drive (11) Check top of expansion tank for air, check
concentration.

Any thoughts?

Brian Doss
'88 Weekender, Queequeg