Having burned myself one too many times while changing my bike's engine oil, I have to ask, is warming my engine before an oil change worth it?
My understanding of multi-weight oil is that it will flow when cool yet protect when hot, right? So, the idea of warming an engine before draining old oil seems to be a holdover from the days of single-weight oil when, I assume, cold 40-weight would flow like cold butter. Or does 10-weight or 10W-40 flow like milk when warm? Or is that secondary to getting any contaminants thoroughly suspended in the oil as it drains? And should the oil filter not take out any contamination?
By: news (offline) Monday, 06 April 2015 @ 09:21 AM ICT
I've heard countless opinions and specific directions on both sides of the hot or not-hot engine oil matter, and I've concluded that in the end – you know, in the big picture – it really doesn't matter that much. Oil companies generally suggest changing oil when the engine is warm, but even they say that it's not a big deal either way.
Personally, I prefer to change oil on a warm – but not hot – engine. Regardless of its weight rating, oil will flow more easily when warm than cold; so, I will run the engine long enough to get a bit of hear in it, but I'll shut it off well before it reaches full operating temperature. I then let it sit for 15 or 20 minutes before beginning the oil change. That way, I don't get scalded if oil happens to make contact with my skin. And the combination of warm oil and theat 15 to 20 minute cool-down period has allowed oil to more easily drain from the top end into the crank-case or sump...