What is this sound???

joserw said:

I changed the oil last week and no metal shavings. I'd like to think positive, could it be anything else?

Click to expand...

You would almost never "see" tiny metal fragments in the drained oil. Why? Because the oil is run through an oil filter. Any metal fragments would be trapped inside the filter. Only huge chunks of metal would be trapped in the bottom of the pan.

To find out if there is a problem, it's necessary to cut the oil filter open and inspect the filter element. Any metal bits can be seen trapped on the outside of the filter element.

After I had an experience with a failed motor, I now have an oil filter cutter.

I'm going to venture that there is a zero-percent chance that it's a cat.

Can you isolate the noise? If it's coming from the front of the engine -- under the timing chain cover -- there's a remote chance the noise is related to the chain guides or tensioner arms. But honestly, that type of noise is almost invariably associated with the reciprocating assembly...

I wouldn't replace the cats: that's potentially hundreds of dollars of parts. I would get the car on a hoist and try to reproduce noise in neutral with engine RPM while a guy under the car checks the source of the noise. If it's more prevalent from the oil pan than the cats you'll have your answer...