powerwash

[Triple HHH]

can u do this to the engine aslong as ait intake and battery is out the way or blocked off??

i have alot of oil thats dripped down the engine over the years and its not the most spacious to get into with a brush etc

[pcc]

rocker gasket leaking i bet:)
you can do but you are better off using low pressure like a hose.
using high pressure noramlly means water ends up where you dont want it.

when ive done my gt before ive used the garden hose. spray on your degreasing product, p21s autowash or megs d grease are both good, leave to dwell and rinse. you may need to repeat this process multiple times but it will shift eventually
if you do use a pressure washer steer clear of your two black boxes, one on the left and one at the back of your engine bay and as youve said cover your filter.

[Triple HHH]

good guess lol never seen a fiat that didnt leak from the rocker cover :p

well thats a bonus seeing as i dont own a pressure washer yet :)

cheers