heya m8 on a cylinder leakage test or leak down test witch eva u prefer to call it u should have a compressed air line and a gauge that u can plug the airline in 1 side and a air line cuming out of the other and it will have 100% and 0% readings on the gauge. take all the spark plugs out of the engine and put the car in a low gear. 4th is what i usaly use, u should have a adapter that fits in the sparkplug hole witch u can plug the airline on to and it will fill the cylinder with compresed air and u should get a readng. also on the cylinder u are testing u need to set it up as if it was about to spark (fireing number). once the cylinder has a reading if its not 100% u have a leak just take the dipstik out and check for air leaks (compreshon rings no sealing ) and round the exhaust back box for the nois of compresed air. if u dont have the equipment got to your local garage m8 they should have everything thear to do it