Originally Posted by GMR
Having a problem getting the drain plugs out. The engine is in the car. The block is a 3970010 casting. If I break them or some other bad news, I'm thinking my only option would be to drill them out and try to tap the hole to a bigger size. Are there other options?
My goal is to change the coolant but I don't want to create a disaster to accomplish that.
If the block hasn't been hot tanked before, don't be surprised if you manage to get them out and little or no coolant comes out- they are sometimes clogged up w/scale and rust. Take a length of coat hangar and poke around up in the hole and you'll loosen some of the crud enough to get some drainage out of them. Once you get some flow, flushing w/a garden hose and poking w/the wire will loosen/remove more crap until you get a good flow.