Thanks you all guys for the helps. I went home and tried all the techniques you guys suggested and unfortunately, the noise grow louder so I shut it off and covered it up with a car cover and have a couple nightsless sleep. couple days after, I starte it up again and it took me like 15 minutes to get it start and the noise went away mysteriously with no explanation but its also lead to a new problem......I will mention it here but I think it would be best to start a new post. the noise went away and i did a copression test and the following results. 4-pistion=120, 3-piston=120, 2piston=130, and 1-piston=130 any idea whats happening?? What do you guys think that cost my all motor engine to have such a low compression??? the car show now sign of oil leak, not a drop of oil or oil stains on the motor. the motor is flawless, one of the cleanest motor ever. no unsusual smokes comming out of the exhaust. If haead gasket blew, then there will be oil leak. and if piston ring seal broke, then there will be sign of oil consumption and black smokes. any ideal will be taken into consideration thanks guys.