[san rensho]

Replacing the coolant tank is doable, but a major pain. I did mine recently and I still bear the scars on my hands. The main problem is getting the hose clamps off the hoses that are attached to the firewall inside the engine compartment, that are very difficult to get at and in a very cramped space. If you are going to do it yourself, I highly recommend that you get a cable actuated spring clamp removal tool. There's no way I could have done it without it.

As far as the water pump goes, it's not leaking and the bearing has no play in its, it doesn't need to be replaced, but many people replace the pump after it gets 30 to 50,000 miles on it as preventative maintenance. The water pump has a plastic impeller, and when the water pump goes, often with little or no warning, the impeller disintegrates and can send little pieces of plastic into the cooling passages of the engine, causing a blockage and cracked head/engine block.

If you are going to do the water pump, then I would recommend that you also do the motor mount.