Main Bearing getting noisy

[jpistos]

1989 Camry V6 Auto trans. Only 150K, but this is my sisters cars, there may have been times when the oil changes were ... optional. Anyways the mechanic says the noise she hears is a main bearing going and it would cost $5k to swap a motor out w/ a rebuilt. Any ideas or experiences w/ oil additives, treatments, synthetic, etc to squeeze a few more miles out before taking it to the bone yard?
Thanks!

[RickMN]

Normally I wouldn't recommend additives. But since you've got nothing to lose, try Lucas Oil Stabilizer. It has visconsity improvers in it that will thicken the oil a bit. You're in FL, so you don't have to worry about cold winter starts. If it helps, fine. If not, just drain it out with next oil change. You can get it at any auto parts store.