I may not replace it if it isn't leaking but I would probably buy an expansion tank and level sensor just to have on hand, at 119,000 miles if your's hasn't given up the ghost yet, it's in borrowed time... everything else looks solid. That said, while you have the entire front assembly apart you may want to go ahead and clean your vanos solenoids and replace the o-rings, will be two large o-rings and two small o-rings, pretty cheap and very easy while you're in there. For $25 bucks +\-, you may want to grab a vacuum pump rebuild kit as well and possibly, proactively replace the vacuum tube running from the pump to the brake booster. If that one way valve fails it will (can) suck oil into the brake booster and then you're up dooh dooh creek...