Funny sound with 2004 Volvo S60 AWD

When I start my S60 in the morning it makes a loud noise when starting for 10-15 seconds and stops. It kindof sound like blowoff from the turbo. It will make the noise if the engine it then revved up to approximately 1500 rpm for the first few times the engine rev’s up to that speed then quits after that. I was wondering what was up with my car

You need to better describe the noise. Is it mechanical knocking, tapping, pinging? Rhythmic or random? Whistling or swooshing?

It could be a the cleaner is loose, or the ductwork to the airbox is disconnected somewhere.

Its a steady, deep throaty sound. there aren’t any intervals with the noise until it just stops. Its not knocking associated with using the wrong type of gas. It almost sounds as if there isn’t a muffler.

One possibility is a very thin crack in the exhaust manifold.
As the manifold heats up and expands, the crack may close sufficiently for the noise to cease.
Then, when the engine and manifold cool down again, the crack re-opens and the noise returns.

This is just a theory, but since Volvos are prone to cracked exhaust manifolds, this is something worth investigating.