Why does Ford recommend the first antifreeze change at 100k and then 50k after that? Is there something special about the factory fill? Perhaps an additional additive that makes it last longer? I'm at 73k now and I'm wondering if I should just go ahead and do a drain and fill at my next oci @75k or wait until about 90k. My car uses VC-3 orange.
Also, is it a good practice to replace the thermostat when doing a drain and fill of the cooling system or is it one of those "if it ain't broke, don't fix it" type of parts.
Also, is it a good practice to replace the thermostat when doing a drain and fill of the cooling system or is it one of those "if it ain't broke, don't fix it" type of parts.