This question goes across different models that use the KA24 engine. According to the service manager at the local dealer, putting a good Group II SAE 15W-40 SL oil in this engine often causes noise in the hydraulic lifters and loosens up the timing belt tensioner, causing it to make a flapping noise. He says that he just has to drain out the good oil and put in a cheap group I SJ or SH and the noise goes away.

He says these engines just don't tolerate good oil. I can't understand how this could be.

Does anyone have any experience with oil, noises, or anything strange in this engine?