no top-end power
 

My D24T (fitted in a Land Rover) has developed a symptom - whereas it used to be quite free-revving it has lost some top-end power. Near the end of the rev range also the exhaust note changes - becomes harsher and snarly.
Turbo seems to be spinning fine - engine is otherwise normal. Any ideas folks?

Have you checked the fuel filter?

that's a good idea. I'll have a look, thanks.

Is this the fuel filter? And if so, can some kind person give me the procedure?

Yep that's the fuel filter. Easy to replace, pull old one off, some have a center sealing gasket that will need to be removed from the threaded nipple, some filters have it attached to the filter itself. If the new filter has a "loose" center gasket install it on the fuel filter bracket's nipple with clean hands and with fresh diesel or ATF, fill new filter slowly to the top with fresh diesel or ATF and install.
Start engine and let run for a few minutes to make sure any air bubbles get out of the system.

Anders is right

a) what's the weird plastic thing underneath?
b) is that an air bleed screw on top?

A) that is for draining water out of the filter as it's a water block type filter.
B) that is a bleed screw, only works when you have some sort of supply pump.

I see. So the bleed only works if the filter is under positive pressure and the drain - well I've obviously ignored that...

Sorted! :) Ten minute job, and an instant cure. Thanks so much! Happy New Year.

jrtb