Was noticing over the last few weeks that the 3L engine in my '01 lw300 was getting noisy when started in cold weather. One day it was particularly noisy and I investigated. Got over 150K on the car and water pump/timing belt were replaced last year. To my great relief, the noise was a failing serpentine belt tensioner. New part from Saturn ran $130 list and a buddy with a repair shop got it for me for his cost of $111. Typical of most things on this car, took 10 minutes to remove old part and better part of the next 30 minutes to install the first bolt to remount the tensioner. Finally used a mirror to see what I was doing since there was no way to directly see where it was fitting into. Tried using a philips screwdriver in one of the bolt holes to find mounting hole... a real pita. Once one bolt was in, remainder of job took another 10 minutes.
Payoff was when I started the engine and heard how quiet it was, I thought at first that the belt had slipped off. All good though. Engine also seems to run better. Wonder if the rattle in the tensioner was being picked up by the knock sensor and retarding timing.
Oppie