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Subject:Re: Purging Cooling System of Air
From:David Brodbeck
Date:Thu, 4 Mar 2004 16:46:10 -0500

On Thu, 4 Mar 2004, Daniel Stevens wrote:

> are the procedures any differant for the inline 4s or factory diesels.?

Similar, but easier.  There's no bleeder in the engine bay, just in the
radiator.  No need to lift the front end, either.

Bentley's procedure works pretty well.  Basically, open the heater valve
and radiator bleeder.  Pour coolant into the expansion tank until it stays
full.  Have a buddy stand up front by the radiator bleeder.

Start the engine, grab your bottle of premixed coolant with one hand, and
grab the injector pump throttle arm with the other.  Rev the engine to
2000-3000 RPM and start pouring.  It'll suck in coolant so fast that
you'll barely be able to keep up at first.  Just keep it revved up and
keep pouring until the expansion tank stays full.  Then put the cap on
before you let the engine idle down.  Meanwhile your buddy is watching the
bleeder, ready to close it when no more air bubbles come out.

That's pretty much it.  It's pretty quick.  I then take the van on a short
drive to get it up to temperature, then crack the bleeder open with it
idling to let the last bit of air out.  Then I put some coolant in the
overflow bottle.  Any remaining air will work its way out through the
expansion tank and be replaced with coolant from the overflow, in my
experience.

If you don't have anyone to watch the bleeder for you you can still do
this, it's just messier and takes a lot longer.  Just make sure you put
the cap back on the expansion tank before you let go of the throttle to go
around front and watch the bleeder.  Coolant *will* overflow back out if
you don't.  (Don't ask how I know this.)

David Brodbeck, N8SRE
'82 Volkswagen Diesel Westfalia
'86 Volvo 240DL wagon