[Steve40th]

Most people talk of quarts in a mileage sense. Well, I am thinking that we need to really see how are cars use oil.
There are many variables, such as engine size, rpms due to gear choices, steady state vs city driving etc etc.
What can we honestly due to figure out our oil consumption. I mean, if I tracked a car for an hour and used a quart after 250 miles, yet on the highway and I am cruising in OD till I hit 250 miles and I use no oil, what has changed?
I am thinking one thing tells us how we are doing with oil consumption, and that is compare it to fuel consumption.
I am no engineer, no mathematician, but if you get 10 mpg and use 1 quart of oil, then you get 20 mpg and use 1/2 quart, you will eventually see a trend.
anyways, just a thought.

 

[OldVetteFan]

Steve -

Just off the top of my head, I would think that there are two rates of oil consumption.

The first is a steady state loss - and that might include some (or most) of the leaks around seals and gaskets. In most cases, you would expect a fairly steady rate of oil loss, irrespective of how the car is driven (ie, city or highway, high or low engine RPM, and maybe even running or not running - just look at the stain on the driveway).

The second is variable, and is dependant upon the conditions and the cause of the leak. If your valve seals are in poor condition,you'll pull some oil every time you start your car (thus, number of starts could be a factor in oil consumption). On the other hand, if your engine is beginning to lose its oil control ring seal, then the harder the engine is run, the more will get by the oil control ring.

This is an interesting thing to consider (I'm a science type by occupation and training), but I think there are practical limitations. Fundamentally, with an engine system, it is generally easier to use a simple rule of thumb regarding oil consumption (ie, no more than a quart every X miles). When the oil consumption rate exceeds X, then it is time to fix it.

Steven

 

[Steve40th]

I know there is a good rule of thumb, but after thinking about it, it doesnt necessarily show people what kind of oil consumption you really use.
My Vette has 3.75 gears, up from the factory 2.59.
My engine is also a stroker, and that uses more oil I am sure due to low tension rings. It doesnt smoke on start up, even after a week of sitting.
But it has a tiny leak on the front water pump gear drive seal, but not enough that any ever hits the ground or the frame.
But, it was just a topic I thought was a good one to discuss.