I have a 2004 Disco and upon cold start-ups, there is a loud roaring noise from the engine compartment. After about 2-3 minutes it goes away and I never hear it again until the next cold start-up. Any ideas/suggestions?

 

Fan clutch lock-up before engine warms up?

 

It appears as though it's the SIA after taking a closer look.

 

It is normal for the fan clutch to lock up when the fluid settles overnight, once the fluid moves around it unlocks.

If your SAI is making that much noise then you need to change the filter to it before you burn it up.