There is a kit available to test for exhaust gas in the coolant. With my kit you add fluid in the bottle then breath coolant overthrough gas through the seringe while reving the engine. If the test fluid changes color exhaust gas is present.

Sounds neat. Where do you get the kit and how much? Gotta be less than an gas analyzer.

http://www.rxauto.com/blocktest.htm

There'* one place. I'm pretty sure napa sells the kit too.

So $40 for 10 tests. $4/ test. Not bad. Thanks, bonneville.