Bought a $38 leak down tester to find my head gasket, turned out to be a $6 radiator cap
I spent two weekends chasing a coolant loss on my 2003 civic. I rented a pressure tester from the parts store, pumped it to 16 psi, watched it drop, and was sure the head gasket was toast. So I bought a leak down tester for $38 and pulled all four plugs, and every cylinder held air fine for ten minutes. I was about to yank the head in my garage in Phoenix in July, which I did not want to do. Then my neighbor walked over, looked at the cap, and said the spring felt soft. I threw on a $6 cap from the store down the street and the pressure held at 16 psi for a half hour straight. I keep telling people to check the cheap stuff first, but everyone online jumps straight to the worst case. Anybody else burned hours on a diagnosis before checking the dumb little part?