Hi, I've had my Tundra for 4 years now. It has 72k, 50k when I bought it, and on every startup it "knocks". It sounds like an exhaust leak but it goes away after a little while. It doesn't matter if its winter or summer, hot or cold it does it. It seems that, lately, it takes longer for it to stop.
I questioned the dealer's service manager and he said all the V8's do it, not to worry. Is this true?
Thanks, Jeff
Yep, or at least very many engines do it. The aluminum pistons fit the iron cylinders just right when warm, but are slightly loose when cold. Aluminum expands more in the heat than iron, and contracts more in the cold. Don't worry. Drive as any engine should be operated, easy until warm. Certain brands of oil seem to damp the noise better than other brands, and you might try a different brand. It is not the fault of the oil, and it really isn't a fault at all.
Ken
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