A Nice pic. It shows how Mclaren didnt exploit all that empty space above the engine that Renault has freed up thanks to the new intake plenum, to relocate some of the cooling system there, like Renault and RB did.
It's quite strange because Mclaren was doing exactly that with the Honda powerunit; many coolers where placed above the engine... This year, Mclaren decided to put everything in the sidepods. But why?
The 2018 Renault had less cooling demands then the 2017 Honda according to Boullier (hence the smaller 2018 sidepod intakes ?) That partly answers the question...
Maybe they wanted to lower the CoG... even the compressor air-filter is placed very low, just above the turbo, not exactly likethe Renault and the RB.
(it looks as if this airbox has been designed around a 2017 Renault plenum)
Nice little NACA intake on the internal bodywork near the turbo/wastegate