I can' t fit anything larger than my 1/2" drive impact with 27mm socket into the space between the radiator and the harmonic balancer. I want to stay away from major disassembly. After removing the starter, the flywheel locking goes into that space to hold the flywheel, preventing the crank from rotating. Then I can apply suitable breaker bar/cheater force to remove the bolt. Lastly, the factory service manual tells me that I only have to replace the bolt if the measured length is over 78mm.

After I bought the factory manuals, I wondered why, what with all the electronic/computer stuff they contain. They are a very good source of mechanical type stuff, after you weed through and find it. For instance, when replacing the harmonic balancer bolt, the spec. is to lubricate the threads with oil, then tighten the bolt to 200 N-m (148 ft-lb), then tighten the bolt an additional 90 degrees clockwise. That last comment helped me to know the darn thing wasn't left hand thread.