For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition
65 WarningEngine Block Disassemble Engine Block
Remove the engine front cover studs-(1).Remove the block heater cartridge, if equipped.Remove the right knock sensor bolt.Remove the right knock sensor.Remove the left knock sensor bolt.Remove the left knock sensor.Remove the crankshaft position sensor bolt.Remove the crankshaft position sensor.Remo ...