Shell, Pennzoil, Quaker State differences in motor oil?

Question

What are the differences ( I use 5w30) and why should I pay more for a daily driver vehicle GMC Envoy with 116,000 miles) that gets the pedal floored only ocassionally.

Answer 1

Consumer Reports did a test of motor oils, measuring the wear on major moving parts in the engines of a fleet of taxis in New York City before and after a period of time.

What they found in their test was that among oils that met SAE standards (your owner's manual will tell you what oils those are for your car), there was no difference in wear over time and use -- EXCEPT that full synthetic oils like Mobil 1 or Valvoline MaxLife Full Synthetic provided better protection.

The reason is that synthetic oils have a better viscosity index. That means that the thickness/thinness of the oil changes less with heat, so a hot engine does not thin the synthetic oil out as much as ordinary oil, allowing it to keep its protective film better.

This was not the most severe test, however. Most wear in an engine happens during a cold start, when the engine has been sitting for a long time (overnight, or after it has been sitting in a lot or garage while you work), and the oil has had time to drain out of the heads and away from the pistons.

At that time, the oil is thickest, because cool oil is thicker than warm oil, so when you start the engine, it takes a little longer to get where it does what oil does -- provide a microscopic film between moving parts so that they don't scrape together.

That's where the synthetic oil gives its second advantage, again from its superior viscosity index. It doesn't thicken up as much in a cold engine, so it is better ready to flow and protect the engine when you are cranking it up from cold.

Another advantage is that synthetic oils are less volatile. That means that the thinner fractions (parts) of the oil do not evaporate as readily under hot engine conditions, so that between oil changes, synthetic oils stay more stable, providing more protection for longer.

Answer 2

Quaker State Vs Pennzoil

Answer 3

This Site Might Help You.

RE:
Shell, Pennzoil, Quaker State differences in motor oil?
What are the differences ( I use 5w30) and why should I pay more for a daily driver vehicle GMC Envoy with 116,000 miles) that gets the pedal floored only ocassionally.

Answer 4

I'm not an expert, but my advice to get the most from your money is to buy a "SynBlend" of both petroleum and synthetic oils. My Motorcraft (Ford) dealer installs a synblend Motorcraft oil for every oil change. I think that says Ford thinks that's the best motor oil for now. However, I use a full synthetic Mobil One in my best car.

Answer 5

There's an old saying; "opinions are like rear ends, everyone has one and they all stink". The only scientific evidence of the differences in motor oils was by Consumers Reports a few years ago. They used a NY Taxi fleet with all new engines and ran them for 75,000 miles. Tested name brands, synthetics, and el cheapo generics with 3,000 to 6,000 mile change intervals. At the end they tore down all the engines and weighed the bearings on a gram scale to see how much wear had occured. Their findings were "no significant difference" between oils or change intervals. Their recommendation: shop for oil by price just making sure it has the seal that says it meets SAE standards for gasoline engines and that it is the viscosity recommended by the manufacturer of your car. Basically the expensive synthetics are a waste of money.

Answer 6

Mineral based oils all have to meet the same specifications and are made out of the same base stocks, if you want better oil go with a synthetic. My choice is Mobil 1. Factory fill on high end sports cars including the Corvette.

Answer 7

Oil is one thing that you get what you pay for. Cheap oil is just that, Cheap!