Originally Posted by theaveng
I recall back in the distant past (2003) some insighters tried running just 2 quarts of oil. They said it gave them better fuel economy. Any thoughts on that?
Yes, I have a thought.
I would never do it!!
In this case I do not try to out-guess the engineers who designed the engine and specified an oil fill height in the crankcase.
Let's say for example we have an engine that normally takes three quarts, and we only fill it to 1.5 quarts.
The oil level is now only 1.0 inch above the oil pickup in the crankcase, which for straight-line driving would still be adequate. Right?
Well, now we are driving and we have to swerve around an obstacle in the road, so we yank the steering wheel side to side to avoid the object.
Now what happened to our oil level that was only 1.0 inch above the pickup? Correct, the pickup ran out of oil because it sloshed heavily side to side due to the action of the car.
The engine was starved for oil for a short period of time, but the damage is already done.
I always fill any engine that I maintain to the highest level on the dipstick, as this also maintains a higher quantity of oil in the engine.
This higher quantity provides more long-string molecular chains of oil in the engine, which take longer to degrade over time, since there are more of them there. The additives last longer as well because of the larger amount of oil.
To me it makes sense to "splurge" when it comes to engine lubrication.