Dave, if the circulating system is intact, and you do in fact have all
the air out by proper bleeding of the system, then take a very close
look at the small hose that goes grom the the expansion tank cap to the
overflow tank. You may very well have a tiny hole in it that can't be
seen easily. You may want to remove the hose and flex it while you
inspect it. There is no pressure on that hose as coolant leaves the cap
going to the overflow tank so a leak wouldn't show up. But if there is a
tiny hole it, the hose will definitely draw air instead of coolant as
the system trys to back-suction the coolant from the overflow tank back
to the expansion tank.

Also, note that there should never be any pressure in the overflow tank.
On top of the tank, on the side facing the rear of the vehicle are
several - 3 as I recall - vent holes. They cannot be seen unless the
tank is removed. If when the tank cap is removed, there is an expression
of pressure, then the vent holes are plugged up and must be cleaned. A
rare happening but possible I suppose.

Good luck on your hunt for a solution.

John Rodgers
88 GL Driver

Dave Vieira wrote:
> Hello
>
> once again im back with the same problem.  :)
>
> i have the 84 vanagon 1.9 water cooled
>
> I have bleed the cooling system many times yet still
> air is gettin in there i donno how .. i donno maybe im
> not gettin it all out.. but im pretty sure i am.
> After i bleed it . it works good. heat ablasting and
> all damm its nice .. temp is low  and all .. after
> that i let it sit ..   .. till it gets cool again.
>
> the res tank is like almost full and the expanshion
> tank is empty but if i loosen the cap the air rushes
> out and if fills up a bit .. so i bring the res tank
> down to the max line and carry on .. it works alright
> . i get heat then i loose it.. when i want lots of
> heat . it only works for a bit then its ice cold ..
> ... after highway driving lots if idont check it i get
> the light bulb blinkin away and i goto do the cap
> think take the air out and refill it .. empty the res
> tank.  . now im thinking could it be the expanshion
> tank cap .. its lettin the water out. but .. maybe its
> not bring it back in when its needed and thus bring in
> air that way ? .. maybe..  what yea think .
>
> BTW: i did a compression test and the cylinders are
> holding there all good.
>
>
>
> =====
> Dave Vieira
> Hamilton, Ontario
> Canada
>
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