Does anyone know what the bolt highlighted in the photo is? Seems to be leaking oil. It's located under the water pump and appears to screw into the engine block. What do I need to do to reseal the bolt?

 

I know it sounds like a stupid question bit are you sure the oil leak isn't coming from the exhaust cam seal? It looks like there's a bit of oil under the cam gear

 

Photo is not my engine. Only used to identify bolt in question. The bolt is the piston oil cooler jet control valve. It has a copper seal washer to seal it. The bolt was loose. Tightened and no more leak. Had to cut away a small portion of the rear plastic backing plate to gain access, but not too big an issue. If you have a leak running down beside the turbo oil feeder banjo bolt on the engine block, then keep this in mind. Thanks Guys