Dunno about a WBX motor, but for my inline when I had a bad headgasket
causing combustion gas to emerge into the coolant overflow/expansion
tank....I got the motor up to temp.  Then I pulled the spark plugs, which is
really easy on that motor.  I put my compressed air on the inlet to the
expansion tank cap and added about 15psi of compressed air.   Took a
listening device to each of the plug holes and found the leak by listening
for a hiss or the sounds of leaking at the plug hole.  Verified by shining a
flashlight down into the plug hole and I could see some coolant in
there.....then, for fun, I cranked it over with the plugs out.   Big
Mistake!  I squirted very high pressure coolant all over the inside rear of
my van's roof....
   3.5hrs later (+/-) I had the gasket replaced and the van back together,
running sweet again.  Almost $50 for the gasket set, though.

  Don Hanson

On Tue, Nov 9, 2010 at 12:35 PM, Rob <becida@comcast.net> wrote:

> At  11/9/2010 09:47 AM, John Mosley wrote:
>
>> what is the easiest way to determine which cylinder is leaking
>> exhaust gas into my
>> coolant system?
>>                    thanks
>>                                jack     91 vanagon auto  gl
>>
>
> I'd do a compression check, but that's my first answer anytime I'm
> concerned about that part of my engine...
>
>
>
> Rob
> becida@comcast.net
>