Well I went ahead and picked up a tester known as "block check" which tests for combustion gases in the coolant.
The idea is if it tests positive for combustion gases in the coolant then you kill cylinders by removing plug wires then retest until it comes up negative. This tells you which cylinder, or pair of cylinders in the case of our flat four cylinder.
It uses a blue liquid filled to a fill line.
As you squeeze and release the bulb it sucks air in, in this case combustion gasses would get sucked in thru the blue liquid which makes it change color slowly from blue then green then yellow.
[video]https://www.youtube.com/watch?v=NHt1guPR1Ic[/video]
I ran the test with all cylinders firing, the fluid turned green once the engine was completely warmed up.
Then I started over with fresh liquid after pulling the plug wires from one side and ran again.
I kept running it as long as I could but then coolant got sucked in and ruined the test, It didn't seem like it turned color until coolant got sucked in telling me there were NO exhaust gases present (yet)
I need to run this test a few more times, I'm not sure what I'm seeing just yet because I have to make sure it didnt suck in coolant the first time when all plugs were firing. I'm not sure how I'm going to get a accurate test because once the engine temp gets to around mid gauge coolant bubbles up the filler neck and gets sucked into the tester voiding the test. Even if I drain the coolant down it still bubbles up. I dont want to drain too far down so there isnt coolant flowing.
Argh!