The passenger lifters became noisy after the recommended oil change was completed. I used Mobil 1 synthetic 5W30 high mileage oil. I had faintly heard a noise before but upon changing this oil the lifter was really noisy. I parked the Cadillac and began trouble shooting the problem. ( I'm a licensed Mechanic with over 40 years experience). I'm researching the problems known for this make and model. I'm looking for solutions to this lifter problem to prevent an occurrence of this kind in the future. I do not believe that this SRX is a trow-away vehicle and would like to fix this existing problem.