Teekster

2003 C4, 111k miles.

ZuffenZeus

That definitely sounds like piston slap associated with bore scoring. Need to confirm with a bore scope. Watch part 4 of Jake Raby’s series on the subject.

wildbilly32

What B3 said...

85eurocarrera

I think you know the answer, unfortunately…….

Mike Murphy

It does have a slightly higher pitch (tone) than other sounds I’ve heard with bore scoring.

wildbilly32

To me the second recording with the belt back on and the car not still on fast idle from a cold start sounds so much like my car did at a point during the progression of the disease.

mrfeh

Is that all the time, or just at cold start?

Flat6 Innovations

Scope it from the sump....

bantamben

Do a compression test, if it’s that loud your should have some cylinders that will have really low compression.

Flat6 Innovations

Nope. Bore scoring will boost compression values all the way till stage 4. This is due to the oil filling the voids between the rings and cylinders. This makes a compression or a leak down test a waste of time with these engines that do have scoring.
I see cars all the time that pass both tests, and have confirmed scoring. Due to this the cylinders that test the best are often the problematic cylinders.

Visual inspection is the only way to conclusively determine scoring, and severity of the scoring.

Teekster

All the time

blazinz3

Subscribing on this one...

Mine started making a similar noise within the last week. However, its only at start up and lasts about 1-2min, then goes away until the next cold start.
May be time to go down the rabbit hole of flat6 vids

Teekster

Well, after a prolonged diagnostic period, bore scoring is confirmed. 4.0 resleeve here we come! It’s a good thing they have appreciated somewhat.

Teekster

mrfeh

That's a bummer. Sorry man.

One of the reasons I sold my C2 last month.