I have a few questions about coolant replacement ('96 Honda Civic DX).

The Honda Service Manual says to install a new drain plug washer for the cylinder block and to apply liquid gasket to the threads. Where do you buy your replacement washers, a value auto parts store, an upscale auto parts store, or Honda dealer? Is is OK to use Teflon tape instead of liquid gasket?

Do you automatically replace your thermostat when you change your coolant, or do you wait for the thermostat to fail? How about the radiator cap? (I don't have a radiator pressure tester.)

The manual says to use genuine Honda coolant, but unlike automatic transmission fluid and power steering fluid I'm OK with a major coolant brand, right?

I'm thinking about flushing out the system with water, then filling to half capacity with 100% coolant and topping off with water. However, the Honda Service Manual gives 3 values for capacity of my D16Y7 engine. In the Specs chapter they say 4.3 qt for an overhaul and 3.2 qt for coolant change. In the Cooling system chapter they say 3.9 qt for coolant change. It makes sense to me that to achieve a 50% mix I should use half of the 4.3 qt value. No?