I curious how you used the pressure tester to diagnose the radiator. It 
seems that the system would have to be up to temperature so that the 
thermostat would be open, but then the system is under pressure anyway. I'm 
assuming that you can only use this tool to apply pressure to the coolant 
reservoir, or to test the pressure cap. Hmm, I guess you could remove the 
thermostat and then pressurize the system while it's cold. How much pressure 
did you have to apply before the pinhole leaks became apparent?

-Mark
>
>
>On Sat, 16 Dec 1995, Mark McCulley wrote:
>
>> Is it worthwhile to own a tool for pressure testing wasserboxer cooling 
>> systems? 
>
>Considering the coolant leakage problems some have and the length and 
>number of coolant hoses used, I would say yes.  
>
>I recently used mine to diagnose pinholes in the upper radiator.  They
>were too small to leak enough coolant to notice, but would suck in air
>upon cooling after shutoff.  Next trip, coolant is forced out the pressure
>cap, leaving a big air bubble in the radiator.  Without the pressure
>tester, I would have thought I had a small combustion gas leak into the
>cooling system. 
>
>I came across one today for $89 + $30 for VW/Audi adapter. Seems 
>> like it could be useful in the long run, but it's quite a bit of $ for such 
>> a special purpose thing. 
>
>I don't remember what I paid, but it was pricey.  Useful tool though.
>
>Mike
>
>