okey dokes, almost all oil coolers I have seen fitted to car engines, plus with what Thinkauto say, have always been mounted so the outlets are uppermost. Reason given is to avoid air locks.

Now on motorcycles, the oil coolers not only are mounted higher up but invereted. i.e. updisdeown to car fitment.

So why the difference in orientation?

The OEM oil cooler is mounted "upside down" on my car (Fiat Coupe).

I suspect the difference is mainly one of convenience, i.e. having the outlets facing the required direction to avoid the use of extra brackets/fittings etc.

I think bikes have them uppermost to keep the connectors and pipes up out of harms way (and to help remove air)