AoxoMoxoA

First post:

Picked up a 2003 C230K with 109,000 on the clock a week ago today; my son's first car. Car is a 1-owner vehicle, had a clean Carfax, engine is very clean (no oil/coolant seepage) and runs very smoothly, like new. He's been driving the car daily all week without issue.

We changed the oil & filter (Mobil 1 0w40) for the first time yesterday along with the air filter, cabin air filter and new spark plugs (NGK Laser Iridium ILFR6A - 3588).

Started the engine this morning just to check things out and all seemed normal, as it has been. On a whim, I opened up the oil filler cap just to peek inside while it was running, and heard the sound (heard in video linked below) coming from within. Note that this sound is inaudible with the oil cap on.

Is this sound normal?
If not, any guesses as to what it is?

It almost sounds like something is loose and is contacting the camshaft lobes as the camshaft spins...

The car is under a 30-day warranty, and I'd like to be sure that I don't have a major problem on my hands before the warranty expires.

Thanks in advance.

https://www.youtube.com/watch?v=o5uf...ature=youtu.be

FLYNAVY

if my chest were cut open, i'd imagine my heart would sound different too…...

Russell Ormerod

Does the sound get louder with the tappet cover removed?

TTMBCLS

doesnt sound normal with the oil cap off. have u tried looking over the oil pump?

Russell Ormerod

It's just internal engine noise. Compare it to another 271

Kazi04

That is normal noise. You have to remember that these cars use vacuum and crankcase pressures different than most other vehicles.

AoxoMoxoA

Thanks for the reply.

I've just never heard anything like it with past vehicles, including my '96 C280, which internally, was whisper quiet - nice precise valve clicking - even at 274,000 miles.

serialpyro

Hi. Yes I spent lot of time looking for with there's this strange noise and it's normal. Not sexy noise.