M5 Expert (>4000)
Join Date: Aug 2002
Location: Raleigh, NC
Thanked 1,503 Times in 1,027 Posts
Yeah, I'm always amazed at the blast furnace that is the E39 M5 engine compartment. Starting way back in time here with greg's thermocouple data gathering to living with it now for the past 14 years. I've always opened the hood every time I park the car in the garage to not allow underhood temps to soar and bake everything. The lower plenum is hot as fire most all the time.
There's a profound difference compared to the E90 M3 with the S65 and its external, lower mounted, oil cooler and I suppose better airflow management through the engine compartment. It's nowhere near as crazy hot underhood, even after driving very hard.
2019 M2 Competition 6MT LBB, slicktop
2011.5 M3 sedan 6MT Silverstone, slicktop: Dinan front swaybar, Eibach rear swaybar, pins-out-max-camber-up-front, Dinan exhaust, Michelin PS4S, Apex EC-7 9.5/10.5x19
2007 328i wagon Silver/gray: Eibach 28mm front swaybar, E93 M3 rear swaybar, 219M M3 wheels, Michelin PSAS3+
1975 CanAm 125MX2: Stock, original owner