It won't last forever - it is just a temporary get-you-home solution. I would recommend getting it fixed and thoroughly flushed fairly soon. It won't upset the water pump, but the solids in the solution will settle around the engine and in the heater matrix and reduce their efficiency.
The V engines have a coolant drain port down by the sump flange - one or two depending on version. These are almost always blocked by silt and crud by now, but often rad weld type stuff tends to settle in these as well (lowest point in the engine block). When you flush the system make sure you open up the drain port and clear it out. Usually nothing comes out to start with, so the metal inner of a wiper blade works very well as a pokey stick to clean the crap out.
Drain the system as much as you can (ie when whatever is leaking gets fixed), clear the drain port, and then re-fill with 10% coolant solution. Run it around for a couple of hours then let it cool down, then flush again with water. If you can attach a garden hose to one of the heater hoses, that works well to flush everything out. Drain again, then top up with 50% coolant and you should be good to go. 50% on a drained but not dry system will end up about 40% once it mixes with the water that is still hanging around, which is fine for our climate
