GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello, first have you checked the oil and made sure it is topped up and that the filter is in good shape? Secondly, assuming that the oil is ok, sounds like there is an issue with either the timing chains being stretched, or maybe just worn guides. Either way you'll have to tear down the engine somewhat and inspect. How many miles are on the vehicle?
No just start the vehicle up and it will fill with oil immediately. No priming required.
Oil light on? And are you using a factory filter? Also, make sure the oil is at the proper level.