engine knock

[Fd235158]

Hi everyone,
I was wondering if anyone knew what would cause my 2000 tacoma 2.7L to knock. It only does it during acceleration when the engine is cold. Once the truck warms up it goes away. Any advise would be greatly appreciated. Thank you

[corbinwaterski]

Check your exhaust manifold. It might have a crack or leak and when the exhaust warms up it expands and seals itself.

[silvertaco4x4]

I don't know but mine does the exact same thing. I've taken it to two dealerships in the area and both say it is normal. One dealership said it's piston slap, the other didn't specify but just said these engines can sound like they are going to "fall apart" and still be okay. Doesn't sound right to me and I wouldn't have ever bought the truck if I had known I'd be in this position now. I know that the sound was worse this past winter and lasted longer than the year before. I've checked my exhaust manifold and if there is a crack I can't find it. I'd love to know if you ever figure out the problem.

[Fd235158]

I can't find anything wrong with the exhaust manifold. Piston slap doesn't sound like a good prognosis even if it is normal. Considering that this just started at the end of winter something's changed in the engine and there has to be a way to fix it. On a side note it's gotten better with the warmer weather. Does anyone think it may be something wrong with the valves?

[Brian R.]

Valves never knock. If they are out of adjustment, they tap.