My problem is that when I screw the hose of the leakdown tester into the spark plug hose and start letting air into the cylinders, I can feel air coming back out of the spark plug hole of the cylinder I am testing. I am getting a false reading with the leakdown tester with a large discrepency between the two gauges. I tried using teflon tape on the end of the hose, but air keeps leaking back out of the threads. The leakdown tester I am using is the one off of Summit Racing.

 

make sure the threads on the tester are the same and not damaged.

Could he use some sort of silicone or hondabond on the threads to make it seal better? silly I know...

 

or maybe a rubber gasket ?