Rick's Free Auto Repair Advice

Synthetic oil

Should I use Synthetic oil

Lately I’ve seen lots of discussions on auto help forums regarding synthetic oil. I’m not surprised that many of those comments comes from Amzoil dealers. They’re extremely loyal to their brand. I’m not going to diss Amzoil–it’s a good product. But it’s important to keep in mind that Amzoil isn’t a refiner (as far as I know). They buy base synthetic oil on the open market. The same is true of Royal Purple. Just because they don’t refine their base oil themselves doesn’t make them less reliable. In fact, Valvoline doesn’t even refine their own base oils. My point is that if you’re buying base oil on the open market, your claim to fame comes from your proprietary additive package. So let’s focus on additives.

Engine oil is made with about 25% additives. They include dispersants to keep crud in suspension so it can be carried off to the filter, anti-foaming agents, pour-point depressants to prevent the oil from thickening at low temps and viscosity improvers to maintain viscosity as load and temps change, as well as, anti-corrosives, detergents, and anti-wear agents. It’s the anti-wear agents that have gotten the most “press.”

In the past many synthetic oil and traditional oil companies used zinc/phosphorous combos to protect against wear. One additive, Zinc Dialkyl Dithio Phosphate (ZDDP) has been used. But ZDDP has been proven to leave deposits in catalytic converters and the EPA has been leaning on oil makers to reduce or eliminate it. So oil companies have reformulated in order to meet the newer GF-5 standards.

To meet the new GF-5 standards, blenders will use more Group III base oils and that’ll allow them to sell 0W-20 and 5W-20 multi-viscosity oils. To tackle the zinc issue, they’ll incorporate molybdenum disulfide. The new lower cold temperature starting viscosities will get you better fuel economy. But it doesn’t come cheap. ZDDP costs about $1-lb. But molybdenum costs around $22-$38-lb. It’s high right now because of the overnight demand.
It’s also important to note that some off-brand oil companies keep reporting their results based on now-obsolete testing procedures—the engine sequence test. The new testing procedures are known as the Sequence VI-D test to measure fuel economy. It requires testing on late model engines, as opposed to older engine designs. The new test also looks at emission control system protection, testing how much phosphorous remains in the used oil. And the newer oils must meet different test for seal compatibility.

Then there’s the “Dexos-1” issue. That’s the oil GM require on 2011 and newer vehicles. While fuel economy is one of the drivers in the Dexos design, GM really wanted a more robust oil. Simply put, GM wants an oil that’s consistent throughout its life. That’s because the GM Oil Life monitoring system determines when to change oil based on the number of cold starts, engine RPMS, engine load, etc, etc. These are all the factors that affect engine oil life. If you can’t depend on the oil to be consistent throughout its life, then you can’t come up with an oil life monitoring system.
Then there’s the whole oil filter issue. Most cheapo oil filters are designed to last 3,000 miles. Open them up and you’ll find cardboard end caps, cellulose filter media, and nitrile anti-drainback prevention valves. That’s what you get for $3. But that won’t cut it for synthetic oil that are designed to last longer between fills. If you slice open the higher end filters, K&N, Mobil 1, and Fram’s extended guard, you’ll find metal end caps, silicone anti-drainback valves, and synthetic glass filter media. The cost? $8 and up. However, these high end filters are tested and rated for 7,000 to 10,000 miles. Just a note here: If you take your vehicle into a quick oil change place and ask for synthetic, the chances are almost 100% that they’ll install a $3 filter. Yup—same filter for regular and synthetic oil. In other words, you may want to bring your own filter.+

Finally, I’d like to address the issue of Magnuson-Moss. Some people have on the forums have mis-stated the act. If a car maker specifies an oil like GF-5 or Dexos, that doesn’t mean they have to give it to you for free. That’s not what Magnuson Moss says. Manufacturers are allowed to specify the type of oil. Many oil companies make GF-5 and Dexos compatible oils. You do not have to buy them from the dealer. But if you put any other type of oil in your late vehicle, you WILL void the warranty. You can argue all day that you’re covered by Magnuson-Moss. But you’ll lose the argument

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High mileage oil and oil filters

Oil Viscosity Warning

Synthetic Oil Facts and Myths

Synthetic oil versus conventional oil

What motor oil to use

What oil brand is best

What oil should you use

When to change oil

Best Oil filter

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat



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