Coolant caps

[quk@sievers.com (Phil Payne)]

In message <199611190613.WAA29380@oly.olympic.net> Bernie Strub writes:

> While talking with a fellow Audinaut, whose passion is turbocharging, he
> brought up the fact that there are various pressure ratings for the coolant
> system cap (on the recovery reservoir).

I can well believe it.  The documented tolerances for the WR engine are 1.2 to 
1.35 bar excess over atmospheric, and 1.2 to 1.5 bar for the MB engine.
 
There is an Audi service tool (VW 1274) that is basically just a simple hand 
pump and non-return valve.  German service shops _routinely_ pressurise the 
cooling system after doing major work.  You are supposed to pump the system up 
to 1.0 bar and watch for the pressure dropping on the dial - if this had been 
done on my last repair at BRM, I wouldn't have had the problems resulting from 
the improperly tightened turbo coolant pipe.
 
The same tool is used to test the cap - it should open between the limits given 
above.  

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club