There is NO reason to have that additional oil cooler if the stock one is working. In fact, with that funky hose setup, I'd say it's a very weak spot for oil blow out and you risk losing an engine if you lose oil pressure at highway speed. Those hoses should be Stainless braided at a minimum.
Honestly, I'd remove that crap and use the stock which is really a Middle-East spec part that found its way onto USA trucks. FWIW, earlier 2F's did not have that oil cooler, so they even run fine without it. Cooler is still available from Toyota, also.