The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Well, so much for "bulletproof" straight 6, motors knocking :(

**Chevy Fleetside** · 05-29-2007, 10:11 AM

Get a piece of hose and while it is running put one end of the hose on the oil pan and the other over your ear.. If it is a rod knock you will hear it that way and you can determine where in the pan it is the strongest.. If you hear if from down there then you need to take the pan off and figure out which rod it is.. You will need to take the rod cap off and look at the crank. If the crank is not scored you can replace the bearing.. If it is scored then you will have to have the crank machined.. If you have a machanics stethescope (sp?) then you will not need the hose..

05-29-2007, 10:11 AM	#2
Chevy Fleetside Registered User Join Date: Sep 2006 Location: San Francisco Posts: 4,787	Re: Well, so much for "bulletproof" straight 6, motors knocking :( Get a piece of hose and while it is running put one end of the hose on the oil pan and the other over your ear.. If it is a rod knock you will hear it that way and you can determine where in the pan it is the strongest.. If you hear if from down there then you need to take the pan off and figure out which rod it is.. You will need to take the rod cap off and look at the crank. If the crank is not scored you can replace the bearing.. If it is scored then you will have to have the crank machined.. If you have a machanics stethescope (sp?) then you will not need the hose..