Verified answer

Nope.

Low coolant over time is normal.

Water tends to evaporate a little every day through the vent on the reservoir cap.

If after you refill it, it goes down in a week or sooner, then I would consider having it checked out.

Yes, it is removed by some but you need to know the reservoir

should never be full all the way up. Either way keep an eye on the level if it keeps getting low , you have a leak in the cooling system. REMEMBER never open cooling system caps while the engine is hot

no they shouldn't have to drain the radiator to replace the oil cooler lines, check for a leak or maybe just evaporation.