Hello all
If you are looking for oil coolers there are several things that you must consider. First what flow rate can it maintain. Engines such as the type 915 and 916 have a much larger inlet hose size requirement than the standard 912 series do. Try to avoid excessive use of adaptors as sleeves and bends can greatly affect flow. The bypass internally is an absolute must to avoid thermal shock of the oil when the thermostat opens. Most thermostats will list a 10% bypass valve internally. If you are looking for something for aircraft then there are only a few.
One suggestion, especially if you are in Europe, if from Franz in Germany. You can find it on their web pages in the accessories catalogue they list. Unlike most others this is designed for 95C operation rather than 80C (80 is more an automotive standard)
Cheers