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Old 05-19-2023, 01:16 PM   #7
Yamariv
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Join Date: Oct 2022
Location: Regina, Saskatchewan
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Re: Rod Knock when cold - Ever had this happen?

Quote:
Originally Posted by Accelo View Post
I suspect it's piston slap not a rod knock. The piston warms up and it goes away.
Typically the colder it is and the longer it has sat the worse it is.

My 2000 Silverado has been doing that since it was new and it has 175K on it now.
Cheers
You might be on to something!! Here's a bit of what I found for piston slap, sounds like what I have. Biggest thing is that it goes away once warm.

The engine has good power for what it is and doesn't burn oil.

"-Piston slap is a light tapping noise that is more prevalent when the engine is cold, while rod knock is a heavier, metallic sound that gets worse as the engine warms up.

-Piston slap is caused by the piston slapping against the cylinder wall, while rod knock is caused by the connecting rod knocking against the crankshaft.

-Piston slap is more common in engines with aluminum pistons or cylinder blocks, while rod knock can occur in any type of engine.

-Piston slap is typically not as loud as rod knock.

-Piston slap usually goes away when the engine warms up, while the rod knock gets worse.
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