Valve Train Rattle at Higher RPMs

[Stephen31201]

I thought it was detonation and the knock sensors were just bad. But I just made the switch to E85 (Thanks Lito) and I am still hearing it around 5600 and up. The motor has 88k on it. Any ideas?

 

[weather man]

Have a friend rev while you listen carefully. See if you can pinpoint where the noise is. Harbor Freight has a mechanics stethoscope for $3.99.

http://www.harborfreight.com/mechanics-stethoscope-69913.html

 

[Stephen31201]

Is it ok to free rev to redline like that?

 

[weather man]

Is it ok to free rev to redline like that?

No problem. There is no load on the engine.