That's weird you are getting bubbles in the overflow tank.  That
would mean the pressure cap on the coolant tank is releasing.  Could
it just need a new cap?
Edward

At 09:13 PM 1/16/2008, John Runberg wrote:
>Slowly have been playing w/ a 90 GL that's had a shload of issues.
>We're down to "hobby" status on this one as no-one in their right
>mind would keep fixing things :)
>
>Back-story:
>Have replaces a series of failed parts located by observation
>(coolant leaking, etc...) - radiator, some hoses new and some
>reattached, main coolant and overflow tanks + sensor.
>
>Situation:
>Consistently have been getting air into a properly bled system (by
>list procedure, Bently, two separate specialty shops). Has had
>pressure test done & system holds pressure with no leaks visible -
>HOWEVER smell says there *might* be a small leak @ rear heater core
>(have not dug in quite yet). Amount of air can be several seconds
>when front bleeder is opened after a 10m drive.
>
>Latest:
>Noticed steady stream of air bubbles in overflow tank (behind
>license plate) yesterday. At idle, 2-3 bubbles per second. This is
>on a (nasty engine rebuilder) engine installed by PPO perhaps 30k ago.
>
>Opinions?
>
>As mentioned, we're into hobby status here. $$$ will be spent first
>restoring the Westy, but hate to drop the investment in this
>bottomless pit :) so keep pluggin on. Heads? Reseal or replace? Pull
>'em and find out? Have talked to Hans and Karl about engine
>conversions, but just want to locate this prob first.
>
>thanks,
>
>john