Originally Posted By: ArcticDriver
Originally Posted By: 69GTX
There are some vehicles when driven/cornered hard don't appreciate being down 1 qt. of oil. In fact, in some cars it's recommended to be up to 1 qt over full prior to driving it hard. While this doesn't apply to the OP if they never corner hard, it could apply to others.
While I agree it's preferable not be down 1 qt of oil for 500 miles, it's a stretch to compare that to being down 1 gallon in your coolant, which literally could uncover most of your radiator. My radiator holds approx 1 gallon. I could survive quite fine down 1 qt oil. Running without coolant in the radiator for 500 miles would produce a mess.
One possible downside of adding a fresh quart of oil is that it will/could work against the current oil to try and break down the tribofilms you spent 3,000 miles building up, something that you don't want.
I don't think it is a good practice to encourage ovefilling by a quart any more than it is to encourage underfilling. In most all of the literature I have read, the concensus is overfilling is as bad as underfilling. Why not just keep the oil between MIN-MAX ?
How does the topic of coolant enters into this...it is apples to oranges, right?
Tribofilms?
I think it is better to add a quart of oil to keep it above the MIN level than to be concerned about tribofilms...but that is just me.
Cheers
The overfilling is really only recommended for track use IMHO. We always overfill a L for track use. But that is mainly because high G's can prevent the oil from draining down from the head, which can cause starvation.
Oil is the coolant for the bottom of the engine, so it does have a similar function to coolant.