Use a little red loctite, not a bunch. There should be a flat and lock washer on all three bolts as well. Too much loctite is a waste and can just cause trouble down the road. I only use a couple of drops on any bolt I put it on for basic motor work.
Grease on bolts, in some instances, can be used where getting precise torque numbers is needed. You can torque a rusty bolt to a spec, but it might not be tight because the rust put up resistance that resulted in the torque wrench indicating a false read. The ideal scenario is to clean any rust, old loctite, corrosion off the bolts and out of the bolt hole (chase the threads) with any motor work. That level of cleanliness isn't needed here. Make sure the bolt threads are clean and free of grease so everything spins together smooth and the loctite can make a good bond to clean metal.
