Contour Enthusiasts Group Archives Forums General Troubleshooting Knocking above ~3500rpm

For about 8 months or so, my car has had a loud knocking noise coming from the engine. It does get fast as rpm increase. I dont think it's a spun bearing since it's gone so long without dieing. I also have really bad timing chain chatter at cold start up and while shifting (i.e. load to no load). At idle, everything sounds fine. I've searched and nothing seems to quite fit my symptoms. I have no loss of power, just the knocking noise. Any ideas?

this is the second engine i've had in this car. first engine was replaced ~ 23k miles ago.
v6MTX

No codes?

If it goes away when using high octane fuel it could be the EGR system or the Knock sensor.

Otherwise it's probably wrist pins or maybe piston slap.

Use a mechanical oil guage to make sure you have adequate oil pressure.

Correct, no codes show. What exactly is piston slap? Is it when the piston hits the head? Should I start investing in a 3L or is this just an annoying sound that I have to put up with? I'll try the higher octane gas.

I tried seafoam a few months ago, but I havent tried using it in the fuel tank. I'll try that. Keep the questions/ideas coming, i'd like to get to the bottom of this before it's too late.

thanks everybody

I'll check under the car today. When used the seafoam it just smoothed out my idle a little bit. It didnt do anything for the noise.