cold mornings are here, i got out of my IS250 to get something from the trunk while it was warming up and the noise from outside the car sounds a bit strange. Not as smooth sounding. It sounds a bit like the injection tappet noise but much louder but the injection tappet noise i've always had and it can really only be heard if i open the hood and listen. But this noise is a louder version of the injection tappet noise but clearly can be heard from outside. At first i thought maybe waterpump or the belt, but waterpump bearings dont make that noise and the noise disappears after driving a little and once car is warmed up a little.

My oil change is due soon, i've topped up my oil recently and will be changing oil and filters in about 1k miles.

If it was the belt, would the noise disappear when warmed up like it does?

 

I think you maybe hearing the same thing. I believe it maybe the direct injectors that are making the noise you're hearing. The 250 motor has direct as well as the more conventional port injection, as direct injection is slowly making it into newer cars. The quickest and direct way to tell if a car is direct injected is if you can hear a ticking sound when the car is running. If it is really the direct injectors you're hearing, then it's quite normal and you're in good shape; it's probably louder than normal because of the cold weather (if that is what you're hearing). Most bad belts I've heard and had to fix usually squeal bad at startup and then quiet down as the car warms up.

My 250 sounds like a pick up truck when I have a window down going through a drive thru. Lol.

 

My wife's 2008 IS250 was taken to the dealer for something similar (sound wise) and it was something with the valve seating.
Total engine rebuild done under warranty.