MLWRS18

My 02 Pathfinder (VQ 35) has developed a valve train noise, like a tapping sound.

I took it to the local dealer and this is their diagnosis:

"Check valve clearances and find #1 exhaust lifter collapsed"

The fix according to them was going to be around $3,000 as the cam shaft needs to be removed, which requires the timing chain be removed, which requires the motor to be removed from the truck.

As this valve is for the right rear cylinder, my question is: can the lifter (the "bucket" style they tell me) be replaced without totally removing the cam shaft? IE, could the cam shaft be loosened enough to be able to lift up the back end and place a new lifter in without having to take the chain off? Grasping at straws maybe but worth asking.

The dealer suggests I just run it as is as they do not believe there will be any long term impact but I feel this tapping can not be good for the cam shaft.

Thanks for any input you may have.

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2002 Nissan Pathfinder Chilkoot, 150,000 kms.