metro engine noise

[Ultra-Orange]

I am beginning to think the lifters are the cause of the noise. Following Big Nasty's advice I put a quart of ATF in the engine and have driven a couple tanks on it as such, The motor is now quieter (still a bit of rattle) and alot more friendly when cold and at low RPMs.

Thank you all for the great input!

[Mpdonalson]

Piston skirt slap is a common problem with these. Sounds like a diesel and is loudest when cold and when the engine is under load. I got the same problem. The pistons will eventualy break. The skirts wear out and snap off. Rebuild it (with new pistons) before they do.

[Mpdonalson]

I too replaced all of my lifters. Wasted my $. Sad thing is the engine was supposed to be freshly rebuilt. The builder reused the old pistons. The edges of the skirts were razor sharp.

[Mpdonalson]

Also beware xfi pistons are different than all other metros. They have only one compression ring (zero gap) and tend to be hard to find but are a vital part of an xfi.

[Ultra-Orange]

Thinking it could be piston slap. Engine has 200k miles on it and it wasn't treated kindly, thank you for all your input!