Engine Knock

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Rowdy_GMC

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My 2007 Sierra GMC 5.3 is making the exact same knock as this one in the video.

http://www.youtube.com/watch?v=1Z454WVzXkY

if anyone could help out on what make be causing this, some say its a lifter.

but im not sure of it, i have 89K on the truck use Royal Purple oil. and i never miss a oil change.
 
The video is rather short, and I can't say for sure what the noise is. However, we've discussed piston slap quite a bit lately, which is a diesel like rap noise that usually only lasts less than 2 minutes until the pistons warm up. It could also be a noisy valve lifter, or a noisy wrist pin. It's probably not a connecting rod . If it's piston slap, live with it. If it's a noisy valve lifter, add a quart of Rislone oil additive ( drain out a quart of oil first) , and drive
a while. I've had very good luck using Rislone to free up sticking valve lifters. If it's a wrist pin , and the noise disappears within 2 minutes, then again, live with it. If the noise never goes away, and is getting progressively worse, then it's time to get a good mechanic to listen to the engine. Do everything else you can to help the engine, including using a name brand of synthetic oil in a 10W-30 weight, and buying oil filters with anti-drainback valves. Fram, for one, has them in some filters. My 2000 GMC Sierra with the 5.3 liter engine has piston slap for about 30-40 seconds after startup. I don't expect it will be a major problem any time soon.
 
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I heard some lifter noise at start and this bulletin may help. But that said, many owners are not using the correct oil and the correct viscosity 5W-30 oil in these engines and that can lead to problems like this. The AFM lifters are regulated by the engine oil and the wrong viscosity may affect their operation when cold. Only 0W-30 or 5W-30 should be used, anything else get it out of there. Synthetic preferred.


#10-06-01-007B: Active Fuel Management (AFM) Engine, Valve Lifter Tick Noise at Start Up When Engine Has Been Off for 2 Hours or More (Evaluate Noise and/or Replace Valve Lifters) - (Nov 17, 2010)

Models:
2007 Buick Rainier
2009 Buick LaCrosse Super, Allure Super (Canada Only)
2007 Cadillac Escalade
Built Prior to April 1, 2006 with 6.2L Engine RPO L92 (These engines were built with AFM Hardware but the AFM system was disabled)

2010-2011 Cadillac Escalade
2007 Chevrolet Monte Carlo
2007-2009 Chevrolet Impala
2007-2011 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer
2010-2011 Chevrolet Camaro SS
2007-2011 GMC Envoy, Sierra, Yukon
2007-2008 Pontiac Grand Prix
2008-2009 Pontiac G8
2007-2009 Saab 9-7X

Equipped with AFM (Active Fuel Management) and V8 Engine RPO L76, L94, L99, LC9, LFA, LH6, LMG, LS4, LY5 or LZ1
Click to expand...
 
5W-30 and 0W-30 oils were recommended by some auto manufacturers to try to improve their Corporate Average Fuel Economy with the EPA, and not because they're good for an engine. They get the vehicle through the warranty period , but that's all. In particular, engines with over 75,000 miles may need a 10W-30 . Mobil 1 synthetic in a 10W-40 grade has been introduced and recommended by Exxon/Mobil for engines with over 75,000 miles .
Only if you drive mostly in sub freezing weather should you consider thin oils as beneficial to your engine, and even then it's only at cold start. Change your full synthetic oil at 7,000 mile intervals, and use a Fram filter listed as having an anti-drainback valve. If your engine burns/leaks too much oil to use a synthetic, then change at 5,000 mile intervals. Don't overlook air filters and fuel filters too. A bottle of Chevron Techron fuel system cleaner and a little top cylinder oil in the gas ( Marvel Mystery Oil) every four tankfuls won't hurt either.
Nothing keeps intake valve stems and tulips cleaner ( and cleans up dirty ones) better than top cylinder oil. Name brand gasolines already have multifunctional gasoline additive packages, but you never know the level, or quality , of the additives. There's a " Tier" system being used by some oil companies to denote additive levels , but it hasn't surfaced around these parts yet.
 
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getting my truck back today, i had the oil pump changed. to see if the knock goes away. hopefully this solves the problem and i can drive around with no more noise. keep you posted.
 
I had an 88 beretta with the 2.0 litre 4 banger that did that. GM claimed it was, piston slap and was normal since the sound went away when the engine warmed up but, sound or not the car was still a piece of crap.
 
got the truck back. changed the oil pump but still pressure is not getting to the engine. when ever i start it, it makes the slap then it goes away but when i drive the oil pressure drops so low that a message comes out saying "Oil pressure low shut engine off." Going to swap the engine out hopefully the new one wont cause the same problem.
 
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