well if its a piston knock.... ehh. My el camino has one and run it all out most of the time. It's nothing to worry about. Even gm said no to care when the new LS series motors came out the aluminum sleeves would make the piston knock until it warmed up.
Chevy engine knock when cold and under load
- Thread starter ERIC87442
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see yeah im use to that i had an 02 chevy pickup that would do it when cold for about 10 seconds then it would stop, even if i let it warm up or not lol it would always do it for about 10 seconds on take off then never again. i guess it does sound alot like that, only it does it for a long time.
At the dealer way back in the 90's and the 2000's we had a lot of engines that had piston slap while cold , as the engine warms up it gradually goes away. GMC, Chevrolet, even Buick told customers that it is normal. My best friend has a 1999 GMC with a 5.3, he bought new, when you start it the damn thing sounds like the pistons are swapping holes. GMC told owners to use Mobil one and not worry about it..
If you bitched about it long enough they would replace the pistons with ones that have teflon coating on the skirts. And install an oil pump with a floating pick up. (the slide rule boys said some of the original ones where touching the bottom of the pan causing the knock.)
Seriously I couldn't make this stuff up.
If you bitched about it long enough they would replace the pistons with ones that have teflon coating on the skirts. And install an oil pump with a floating pick up. (the slide rule boys said some of the original ones where touching the bottom of the pan causing the knock.)
Seriously I couldn't make this stuff up.The piston noise in the later Vortec 5.3 & 5.7 is not a problem, as stated by GM.
In 95 your Tahoe is the TBI engine (throttle body injected).
You need to determine if it is piston noise or main bearing knock. This engine was common to have main bearing noise, just after start up, when cold. It was due to the plumbing involved on the oil cooler lines and idle speed condition. The cure for most of them was a prom replacement in the computer, which gave the engine a lower idle speed when cold, for a few moments to get oil moving in the system. This knock usually only lasted for 3-4 seconds. Piston noise, if no oil consumption is going on, is not gonna be an issue.
In 95 your Tahoe is the TBI engine (throttle body injected).
You need to determine if it is piston noise or main bearing knock. This engine was common to have main bearing noise, just after start up, when cold. It was due to the plumbing involved on the oil cooler lines and idle speed condition. The cure for most of them was a prom replacement in the computer, which gave the engine a lower idle speed when cold, for a few moments to get oil moving in the system. This knock usually only lasted for 3-4 seconds. Piston noise, if no oil consumption is going on, is not gonna be an issue.
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