Why do engines burn/consume motor oil?

[HerrStig]

Originally Posted By: Chris Meutsch
Originally Posted By: Merkava_4
People get consumption because they're using a thinner oil than necessary.



Then why do Euro cars burn oil using 40w? Are we advocating a 50w in these?
Euro cars get driven a lot harder then in the US with our comatose and frozen to the wheel "Safe" speed limits. Not a fair comparison. Having just spent some time in the Southwest I found that folks drive a lot harder on the 75mph speed limit roads than we do in the frozen north. I checked the oil in the brand new rental every day. Going up a grade wouldn't hurt down there.

 

[camrydriver111]

Originally Posted By: HerrStig
Euro cars get driven a lot harder then in the US with our comatose and frozen to the wheel "Safe" speed limits.


That's somewhat of a myth that was discussed here a while back. Euro cars are actually short tripped a lot more than US cars.

There is a possibility of high speed driving, however most cars there don't see it that often.

 

[HerrStig]

Originally Posted By: weasley
Let's not forget that even a perfectly run-in engine with all tolerances in spec and running the correct oil will 'use' oil through volatility - some of the oil simply boils away and escapes out of the crankcase breather.
PCV valves have replaced breathers here.

 

[HerrStig]

Originally Posted By: camrydriver111
Originally Posted By: HerrStig
Euro cars get driven a lot harder then in the US with our comatose and frozen to the wheel "Safe" speed limits.


That's somewhat of a myth that was discussed here a while back. Euro cars are actually short tripped a lot more than US cars.

There is a possibility of high speed driving, however most cars there don't see it that often.
I don't recall seeing that "myth" disposed of. There's better public transit in most of western Europe, and fuel prices don't encourage short trip use.

 

[Claud]

Perhaps is just the luck of the draw, my niece and I have virtualy identical Ford Fiestas. Yet mine never shows any sign of using oil between changes, my niece will need to add oil every 1500 miles or so.
I had a 1963 Vauxhall that used virtually no oil, it surprised me that a car might not need oil every couple of tankfuls of gas.

Claud.

 

[TFB1]

Originally Posted By: weasley
Let's not forget that even a perfectly run-in engine with all tolerances in spec and running the correct oil will 'use' oil through volatility - some of the oil simply boils away and escapes out of the crankcase breather.

In my experience, unless the engine is highly stressed or boosted, volatility is a non issue... In the real world, my '07 grand Marquis used maybe six ounces(was barely below full mark) in it's last OCI of 11K mi...