I have a 2001 Mercury Sable LS Premium with the 3.0L Duratec (more like Failtec) engine. I have owned this car since new and have religiously changed the oil every 5000 miles with Mobil 1 5w-30 and the cams look as clean as ever from peeking inside the valve cover. No pitting and almost no scoring on the camshafts over the last 163,000 miles of this engine. The car is driven gently and carefully and it is in excellent condition except for one minor detail: the wrist pin on cylinder 3 is dead or dying. The engine burns a lot of oil (something that has significantly gone down since my mechanic added BG RF7 and Liqui Moly to the engine), especially at start up. It is not economical to rebuild this engine at this point unless somebody convinces me otherwise. I have a repair estimate of $6500 from two local repair shops. I am planning on running Castrol Syntec 5w-50 with Liqui Moly next oil change to prevent further wear due to the high viscosity nature of the oil in question. I would like to hear some of the oil experts here chime in on what they think is the most appropriate course of action from here. I appreciate your help.