I recently noticed that with the outside vent opened and the ac off the air coming into the car seem alot warmer than the outside air going by the car. The intake air vents should be isolated from the engine compartment by the hood seal around the edge of the wiper motor cover. This should press against the under side of hood when it's closed and keep hot angine air from getting into the car. This looked OK but I polked around a bit more and found that the cover had warped up a bit in the left rear corner of the engine compartment right in front of the vent opening. This allowed very hot engine compartment pressurized air to be forced through the seal gap under the cover and be pulled into the air vent. An additional screw through the cover closed the gap and dropped the temp alot. May be happening on other 850'S.