Just curious, John.  What would you do if you found, say, that #1
cylinder was the leaker?

It would be prudent, in that you'd be so close anyway, to replace the
bad head (assuming one is bad and it's not just a leaky metal gasket)
and reseal the other.

When I had a bad head, the one with the leaky crack between the valve
seats wouldn't come up to pressure nor would it hold pressure when doing
a compression test.  After removal I still took the heads to a machine
shop for a pressure test to be sure that a head was bad and not just a
failed gasket.  It cost me $35.00 per head.

Mike

John Mosley wrote:
> What is the best way to find out which cylinder is leaking exhaust into the
> coolant system?
>           thanks
>                          jack  91 GL
>                                 84 wolfsburg
>