Help! I Think My Engine Is Suffering From Piston Slap!

Are you a GM truck owner experiencing from loud knocking or excessive engine noise? You are not alone! 1000's of other consumers are also reporting these symptoms. What you may be suffering from is the now infamous phenomenon known as Piston Slap.

What is Piston Slap?

Piston slap is caused when there's too much space between the piston and the cylinder wall. The piston moves up and down in the cylinder and the extra clearance results in a greater amount of rocking in the cylinder, producing a loud knocking noise. Specific models include (but may not be limited to): Chevrolet Silverado, Tahoe and Suburban, GMC Sierra, Yukon and Yukon XL.

Can Piston Slap damage my engine?

GM spokeswoman Deborah Frakes states: "the only known effect of this condition is an audible sound that typically occurs during the first five to thirty seconds after starting" and that "the condition does not create any degradation of durability, performance or safety." In fact, in several of their Technical Service Bulletins (TSB's), GM claims that the "Cold Start Knock" is normal.

Consumers have differing opinions. GM truck owners complain that piston slap damages the engine and causes excessive oil and fuel consumption. Many consumers suffering from piston slap report that the knocking is constant, lasting well beyond the initial start-up, and appears regardless of the temperature. Additionally, consumers argue that the problem lowers the value of their vehicle when they try to sell it or trade it in. In a recent article in the Detroit Free Press, Charlie Vogelheim, an executive from Kelly Blue Book, said "a knocking engine could lower the value of a vehicle by $4000 to $6000 at trade-in."

Is There Anything I Can Do?

If you would like to know whether or not a legitimate claim for recovery under the lemon law is available to you, take a moment to read through this web site and fill out our free case review form or contact any of the attorneys listed. There is no cost or fee for doing so.

The website has been used as a source for some of the information above. is an excellent resource for additional in-depth information on the GM Piston Slap problem.

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