L94 Knocking
Thread Starter
Teching In
Joined: May 2012
Posts: 4
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L94 Knocking 2011 Escalade with RPM dependent knocking (video attached) - 293k, no codes, oil pressure around 30 at idle. Pulled valve covers, all the rockers move, so I don't think its a collapsed lifter, pushrods are straight, looking for next step to diagnose/repair. I'm not familiar with pushrod engines, I've only ever torn down BMW DOHC engines, so looking for advice so I'm not wasting my time doing anything unnecessary.
Joined: Apr 2006
Posts: 3,931
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From: Grand Rapids, Michigan
My LH6 donor car has an oil pressure issue, and it sounds exactly like that when idling. I revved it up and as soon as it built more pressure, the sound went away. Likely is a collapsed AFM lifter, if your engine is so equipped. 30 PSI at idle is a bit low. Even if the rockers are moving, there can be a LOT of slack in the system and it'll sound just like that.
Using an engine stethoscope or better yet a piece of garden hose I would listen while it was at idle to pinpoint exactly where the sound is coming from. I'm sure it increases with rpm and my guess is it's lifter related but I'd start listening along the top of the valve covers to see if I can pinpont which one it is.
