Quote:
Originally Posted by zkv476
Think of this quantitatively. Let's say on a standard 5qt change on a set interval you use up 80% of an oil's additive pack. When you add an oil cooler, all that oil that doesn't come out is additional capacity on top of existing capacity. Let's say that adds a quart of oil. On the same oil change interval you'd only be using 66% of the oil additives in all the oil if you were to change all 6 quarts. Unless you were planning on stretching the oil change interval to use up the additive pack more it's not really worth it. You don't even need to change the oil sooner.
What makes an oil "dirty" is when the additive pack gets consumed and particles go into the oil. The filter catches anything really harmful anyway, and you are still draining out 80% of the tiniest particles the filter can't catch. When you mix in new oil, the new additive pack blends with the "old" oil and what you are left with at the end is 6qts of oil that's slightly used. It's a hassle that's not really worth doing when you realize there's not really a point. It's not as if that quantity of oil that's in the oil cooler will always be there and sludge up eventually. It blends  |
With thinking like this why don't we all change our oil and just put in 4 1/2 qts of new oil, and 1 qt. of used oil. Think of the money we can save...