Might sound stupid but along with the direction of rotation, are the blades configured (if reversible) for the desired direction? About 20years back a mate had a few years of a Ford overheating that no radiator shop could find. he loaned the car to me while the Val was off the road. long story short it overheated on me and I had some repairs to do. While putting it back together I noticed this little detail embossed on the fan hub/blade assy. (before disassembly it appeared to be pulling air through the radiator). reversed the blades, put it back together: no more overheating.
I know it sounds stupid but .....
