cjarrett

I'm pretty sure I know the answer to this one, but does this sound like bore scoring to you? Whats odd is it doesn't have the same rhythm as other videos I've seen. It burns nearly no oil, and drives perfect and strong as ever (though I know bore scoring and it running poorly aren't exclusive).

https://photos.app.goo.gl/61suu9zh4PG2mfpd6

https://photos.app.goo.gl/uHfHw1u6JDsEUhMr7

BucketList

Doesn't sound like bore score. Too random and doesn't increase with RPM. Something is loose like a tensioner or water pump bearing. Take it to an indy. I don't think you need to sweat this one. My 2c.

cjarrett

Thanks Mr. Bucket, I hope you're right. Ordered a borescope and will investigate Saturday first then hopefully not off for an engine rebuild...

I had the same thought too, since it happened fairly suddenly, and only happened when I was driving over bumps or rough start from first gear.

rtl5009

That is not bore scoring.

bgoetz

Wow, I was not expecting that much noise!! To me that sounds like rod knock or what people describe the IMS to be (ball bearings in a steel can).

cjarrett

Sounds quite a bit like this:

jchapura

Pull off the serpentine belt and run engine and see what it sounds like.

cjarrett

Found the culprit, cat is rattle on bank 4,5,6. I can bang it with my fist and hear the same sound, got a stethoscope and its by far the loudest when touching the header & catalytic converter. I put it right on the cylinders for all 6 cylinders and they all sound very similar, but as soon as I touch the header or cat it gets 10x louder, and louder the closer I get to the cat.

Time for either cat delete, gut the cats, or new cats...

cannonball05

An oil analysis wouldn't hurt to ease your mind.

cjarrett

100%, have been doing visual inspections of my oil and dismantling my oil filters since I got the car, changing oil every 5,000kms. Will do the full analysis next go around.

aaks38

If you have PSE, just check all your welds around the exhaust system and the cable which is on that side as the tabs break and you get some weird rattles. This is very common.