Auto engineers have said they see no correlation between today's lightweight "0W-" motor oils, designed to reduce friction and save gas, and excessive oil consumption. But in actual experience, both the prevalence of such lightweight oils and the propensity of more engines to consume oil seem to be moving in tandem. And the test cars that have had this problem have all used such lightweight synthetic oils.

The latest car drinking oil is our $105,000 2012 Porsche Panamera, which is consuming a quart of 0W-40 motor oil about every 2,000 miles. With a 10,000 mile oil change interval, that's five quarts of synthetic oil (at about $8 per) in between oil changes. Several of our drivers got caught out by low oil warning lights and went searching for this obscure lubricant at night while out on the town. And trust us, not every corner convenience store carries 0W-40-weight motor oil. When we talked to Porsche about this, they said this usage was within spec. But we think somebody who bought a $100,000 car probably expects better.

And the Porsche is not the most egregious example. This writer bought the Consumer Reports 2008 Volkswagen Eos test car and kept it for five years. The whole time, it used a quart of equally expensive 0W-20 motor oil every 1,200 miles (accumulating black soot on the rear bumper above the tailpipe the whole way). After several trips back to the local Volkswagen dealer to document the problem, I was told that the VW spec for this engine was, exactly a quart every 1,200 miles. Since I couldn't prove it was using more than that, VW wouldn't help. That car also specified a 10,000 mile oil-change interval, for regular maintenance. By then, all the oil in the sump had been replaced twice.

This problem has plagued other cars, too. In 2006, Mercedes replaced the V6 engine in one of our test cars under warranty after we finished testing them, because of excessive consumption of 0W-40 oil.

Even Japanese cars known for their reliability have lately been burning oil. When I took our 2012 Subaru Impreza to Boston for a weekend, it dropped down a quart on my way back, prompting a late-night search for more 0W-20 weight oil.

Bottom line – evaporation is the culprit.

According to Driven Racing Oil, “The reasons for this consumption are not mechanical, such as stuck rings or loose clearances. The reason for this “vanishing oil” is due to a technical term that also starts with a “v”—volatility.”

A liquid is considered volatile when it can evaporate by converting to a gas or vapor. Almost all liquids have a temperature where they begin to volatilize. Driven’s oil consumption bulletin points out that “Not all oils evaporate at the same rate. Typically, motor oils featuring lighter base oils evaporate more quickly at high oil temperatures.”

Taken from: Yahoo!
and: Driven Racing Oil Publishes Oil Consumption Bulletin - LSXTV

Check your oil more often with 0W__ Oils and don't get too pissed!