Ran the QD 7500 yesterday and today about 16 continuous and have confirmed a trend in this coach. The genset runs fairly hot (215F at times) while driving at freeway speeds. When at a prolonged stop the temp on the genset drop considerably, down to 190F on a 100F ambient day.
I have formed an opinion that the center mounted genset (between the driver seat and front seat Pax seat) and with the genset radiator mounted just in front of the right front wheel well, is not flowing air properly at freeway speeds. Additionally, crosswinds from the left to right seem to make it worse.
My question is, does anyone have a similar configuration, with similar heating problems: if so have you been able to solve this and how.
My theory is that the fins on the intake on the outer skin of the coach are insufficient at freeway speed to overcome the high pressure area behind my front mounted radiator.
I can think of a lot of expensive fixes, I'm looking for something simple. We slept in the coach with Jenny running all night, ambient around 80F and genset at 170F, so working well, except for freeway speed.
I'm thinking of a scoop of some sort to push more air against the high pressure in the genset bay formed by the ram air through the radiator.
Anyone been there?

Thanks

Assuming the radiator is clean and flowing properly you can replace the engine driven fan (about 900 cfm) with an electric fan (Spal 30101509 Medium profile) for about $ 150 and get 1280 cfm. It works for me and I sealed the grille area to reach quiet levels for national parks. That part was expensive.

My gen set radiator is mounted front center on my Spartan chassis, directly in front of the gen set and I have no overheating problems. But yours is mounted off the the right of center?? Are there any baffles under the unit that would keep the air from flowing thru the gen set compartment? Maybe some pictures would help but there has got to be something pushing air away from your inlet when you are on the highway.
Really weird! Sorry I couldn't help.