Glad to see responses to this thread. I respect the packaging engineers with their fan flow (cfm) and shrouding design. I have also wondered about the hood. On my dyt 4000 there is a boxed shroud on the hood that mates with the fan intake. When I put on the oil cooler I carefully preserved it, but put two big hole in the sides of the hood for oil cooler fan intake and exhaust. It would be good for someone to tell us what that shroud on the underside of the hood is expected to do. It does not provide cooler air. So perhaps a guard against debris and grass which cold block the engine fan intake mesh??? IMO the weak link in these ac engines is the head which can easily overheat. Next, measured oil temp in the sump of 280F-300F (or more? ) not conducive to rod bearing and main life. Plus (still a study in process) the head may benefit from a cooler block through conduction.
Once more for new readers...the coils contain transistors (think speaker amplifiers) which only tolerate so much heat. So an overheated engine can affect several areas.
edit: I now see in the previous responses that the shroud (plenum) may be to direct cooler air into the fan. Sorry I missed that response. Still, on my Intek is feels like it merely traps more hot air for circulation.
