This is a long shot, but I'm trying to replace the water pump on my wife's 1988 Toyota pickup. The guy who put the last pump on used a TON of RTV liquid gasket to seal it on, and it might as well be fucking welded in place for all it will move. It's an aluminum engine, so I'm trying not to attack it with a chisel or anything too violent. Any comrades here with car mechanic experience got any tips? I'd prefer not to drop the $400+ the mechanic is going to charge to do it.
This is the answer.
Also, even using an appropriate amount of silicone would have the same result. That stuff is very strong when you have 2 machined surfaces like a water pump.
Whatever you do, OP, worry about protecting the block. The pump is already toast.
You can also take a plastic mallet (a heavier one, say 1-2 lb), and wack on the water pump pulley/shaft (whatever is being replaced). The trick is a quick, sharp hit vertically (and slightly away from the block, if there's room), to lever the pump off. You're just trying to break the adhesion of the silicone on the top edge. Once there's a small break, the rest will give. Doing this won't hurt the block, I've done it countless times over the decades. One of those orange plastic dead blow hammers from Harbor Freight work great for this kind of thing.
This is a good suggestion. I need to get a plastic hammer in that weight range.