Choose Between Three Options

• $43.20 for two conventional 5W-30 viscosity grade motor oil changes (a $128 value)
• $88.20 for two synthetic motor oil changes (selection of 0W-16, 0W-20, 5W20, 5W30 viscosity grade motor oil) (a $240 value)
• $237 for two Mobil-1 Brand Advanced Full Synthetic motor oil changes (selection of 0W-8, 0W-20, 0W-30, 0W-40, 5W-20, 5W-30, 5W-40, 10W-30 viscosity grade motor oil) (a $396 value)

Motor-Oil Viscosity: A Slippery Subject

The oil viscosity
your car needs are usually determined by your cars manufacturer, but is
there ever a reason to switch? Groupon sought out the answer.

Whenever
a vehicle is in motion, engine oil has a lot of work to do reducing
friction between moving parts, keeping the engine from overheating,
preventing components from prematurely wearing down. But there are many
things that can keep oil from staying on top of its workload, and that's
where viscosity comes into play. Factors such as varying starting and
running temperatures, an aging car, or heavy loads on board can all
affect how motor oil performs. Fortunately, auto manufacturers specify
what viscosity level is best for their vehicles, so most drivers never
have to spend much time pondering this subject. But for those who are
interested or who have to make elevator conversation with a talking car,
there are a few basic principles to consider.

Like most liquids,
when oil is cooler its more viscous (that is, slower flowing), and
when its warmer its less viscous. Higher-viscosity oils are most
appropriate for cars that operate at higher temperatures or carry
heavier loads. Lower-viscosity oils work better at lower temperatures
since they dont need to be heated to flow, but they generally offer
less protection against wear.

There was a time when people who
live in four-season climates would use one oil with a higher viscosity
during the warm months and another during the cold months, but
multi-grade motor oils solve that problem by working efficiently in both
conditions. When you see a viscosity grade on a bottle of multi-grade
motor oil says, 10W-30 there are two numbers to consider. The number
preceding the W stands for winter or woolen-underwear season, which
reflects how the oil flows when starting an engine on a cold day. The
number after the hyphen is the viscosity at 210°F, the standard
temperature of an operating engine. (On both sides of the hyphen, a
higher number means a higher viscosity.) What makes this type of oil so
flexible? It's the polymers particles that expand as the oil heats up
and slow down the rate at which the oil thins as it gets hotter.