GMC Troubleshooting Questions? Ask a Mechanic for Answers
Ok , If its a Tap on the upper most part of the engine.....its a lifter or rocker arm......if it sounds like a deep knock ...its the Piston hitting the cylinder head cause by the rod or its bearing that's went out......Thanks Joey : Please rate my answer if we are done.....so as I will get paid or ask more
Hello , Oh the oil pump would compensate for that small oil pressure loss.....which I think its the lifter......because of the tap noise
Sensor will not cause a noise
ok , ill opt-out....let someone else help you...take care
Hi there, I am Cam, can I get your first name please?Can you describe the noise more? Light tapping? Does it change with any cylinders disabled?What scan abilities do you have?
Greg, do you have a scanner? WE disable with the injector balance test, but I suppose you can disable by unplugging each coil control wires one at a time.
Knowing what cylinder will help. Its 1 4 6 and 7 that cut off by the lifters and this can be seen if one failed by removing the valve cover, hooking the coil pack back up and running it. Now on these I have see the odd one with a build up of carbon that when warm would make the pistons carbon hit the head and make a knocking noise.
Ok, sounds good.