how tight should a compression fitting be
asked by: Sergei. Expert Reply: Generally, you will tighten the fittings as much as you can with normal hand tools. If you then do a test after installation by starting the vehicle, check for leaks at the fittings. If you notice even a a drop of fluid leaking out then you will need to tighten them down further.sked by: Sergei. Expert Reply: Generally, you will tighten the fittings as much as you can with normal hand tools. If you then do a test after installation by starting the vehicle, check for leaks at the fittings. If you notice even a a drop of fluid leaking out then you will need to tighten them down further.