Although neither is to be recommended. My oil pump failed and it span up a camshaft in about 30 miles. That was on a Yamaha with only an oil level light as opposed to an oil pressure light. When I'm checking my oil I'm not only checking for level but emulsification aswell, since you quite rightly pointed out that lack of coolant will knacker an engine extremely quickly. Again, I like to do this pre ride, but like I said it's just what I do, it's NOT the definative be all and end all.