[3100]

- with heads off clean carbon from valves completely, use spring compressor tool to remove them one by one and install them back in the same place
- clean top of the pistons also (when you clean the valves and pistons your engine will run like new and will waste less fuel.
- replace thermostat
- use specs to tighten everything back in the sequence suggested by repair manual
- use blue thread lock on LIM bolts (very important)
- also I suggest since you are already down there and depending on the miles I would replace belt and belt tensioner.