CM2350 Oil Cooler Leaking

[Hermjeji]

CM2350, ISX550 - 200,000kms (2015) and about 11,000 hours. No major noticeable engine leaks so far, tonight I was doing my rounds (hadn't looked at this truck in about 4 days) and it looks like the oil cooler is leaking. What's the typical process here, looking at quickserve it suggest pulling it off, doing the plate pressure test on the cooler element, and then essentially replacing it. looks like a pain to get at all 18 capscrews...

Before I do anything else is it worth tightening the capscrews (35-ftlbs recommended and seeing if the cover is just loose). Or is it basically the oil cooler, so get it replaced and replace the gasket.