Pull the cylinder head(s) and change the gasket. If you're getting coolant into the cylinder, it has to be getting there by a piece of debris under the gasket, or a crack in the head. If the driver's side head isn't showing any leakage, you can probably leave it on, but the intake and passenger side head is going to have to come off, unfortunately!
Pull the block drain plug on that side- - - -as soon as you loosen the head, coolant will flood the crankcase if the block isn't completely empty, and draining the radiator won't get the job done.
Jerry
