Oil Cooler - water or radiator?

Hi guys, as the title really. I have a DX in my campervan and have a second hand oil cooler that uses the radiator. I already have the filter housing that takes this but wondered if for any reason water cooler might be better? Cheers

they both work well enough, with the air rad its a case of can you actually mount it somewhere you'll get decent airflow? if not then its probably not worth the effort.  Before you mess about too much i woudl get it runnign daily and see how the oil temps are, I ran my mk2 gti with no oil cooler for a good while and it made no real difference