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Letters to the Editor


Viscosity Is Falling, Not the Sky

Dear LubesnGreases,

In your May 2008 issue, Steve Swedberg wrote a column entitled The Wear-Viscosity Tradeoff, expressing concern about [SAE 0W-20] engine oils viscosity and its ability to protect the engine.

All of this brought me back 25-plus years to the introduction of SAE 5W-30 engine oils. Some in the auto industry asked for SAE 5W-30 engine oils over SAE 10W-30 oils because they offered better low-tempera-ture starting and pumping and improved fuel economy. This request was immedi-ately met with predictions from many in the oil indus-try, and even some in the auto industry, of vehicles with failed engines lining the sides of the freeways. This great disaster never struck. In fact, the move to 5W from 10W oils was one factor responsible for increasing engine life. Most ring and liner wear occurs at low temperature, and lower viscosity helps reduce wear at low temperatures.

Steve has dug up all the old rhetoric and is now applying it to SAE 0W-20 oils. For good measure, he also dusted off the and they took all the antiwear out argument.

So once again we are told the sky is falling – just you wait and see.

I have been waiting for 25-plus years, and Im still waiting.

Bob Olree

GM Powertrain Troy, Mich.

The Wear-Viscosity Tradeoff title of Steve Swedbergs Automotive column jumped out at me because there are many applications such as tur-bine bearing systems where there are wear ver-sus viscosity trade-offs. However, the article was about engine oil, where the correlation is not so clear. Each machine or engine will have its own optimum lubricant viscosity.

While I think it is unlikely that a typical driver in nor-mal driving could statistically tell the fuel economy differ-ence between say 10W-40 and 5W-30 due to variations in driving styles, routes, red-light timing, ambient condi-tions, break-in effects and other factors between one tank of fuel and the next, a well designed and run fuel economy test should easily identify this magnitude of difference.

Swedberg also says that paying the extra amount for fuel economy perfor-mance – its not free – is not a good deal. I dis-agree. As of April 18, the U.S. 4-week average for gasoline consumption was 390.3 million gallons of gasoline per day. A savings of merely 0.5 percent is still 1.9 million gallons per day. In the overall scheme of things this may not be much, but I think it is enough to matter.

For comparison I propose that it is unlikely that a con-sumer could tell the differ-ence in his electric bill if he changed out six 100-Watt incandescent bulbs in his living room with six 23W fluorescent bulbs because the fractions are lost in the fog. However, in this example the energy saving would be measurable and real, and in the long term the cost savings would be real also.

The column states that automakers should stop the lower viscosity madness. This is a strong conclusion and it is unfortunate that no supporting data was pre-sented. The reality is that the high-temperature pro-tection for a 0W-20 is about the same as for a 5W-20. Modern vehicles have much better thermal control than vehicles of the past. If a 5W-20 is operated at 100 degrees C and a 5W-30 is operated at 110 C, then for practical pur-poses the operating viscos-ity that the engine experi-ences is the same.

My experience is that if the consumer uses the oil quality and viscosity grade recommended by the manufacturer and follows the maintenance schedule, then in virtually all cases the engine will live a very long and productive life. Many millions of miles of durability testing were completed before the first 5W-20 oil was recom-mended and I know that the OEMs will thoroughly test any new viscosity grade of oil they might recommend. If the OEM of my next vehicle recom-mends a lower viscosity grade than I am currently using, I will use it with confidence.

If a reader needs some background on this topic, David McFall wrote a good column titled Viscosity, Inching Downward for your November 2006 issue.

Robert Stockwell

ConocoPhillips Lubricants


Ponca City, Okla.

So-called Experts Arent

Dear LubesnGreases,

I really enjoy this magazine. My favorite section is Tom Glenns Need to Know column, and this months really hit the nail on the head (Spelling Out Quality, June 2008).

The so-called experts at the retail outlets are no more informed about oil specifications then the gen-eral public. They just like brand names. Virtually no one knows how to read an oil container label and what those letters and numbers mean. That is sad, since we all trust our $20,000-plus autos and trucks to some-one who doesnt know what SM, SL, CI-4 PLUS, ACEA A3/B3, or MB 229.1 means. In the past 10 years of asking many mechanics and a few DIY customers what the definition of vis-cosity is, I only had one per-son surprise me with the correct answer. He was a chemical engineer.

As for Steve Swedbergs Automotive columns, they are informative but when there is a question about synthetic oil and extended oil drain intervals, he really doesnt seem to like that option. I understand that after over 40 years in the petroleum industry, extend-ed synthetic oil drain inter-vals are a thorn in that industrys side. Old habits die hard.

After nearly 33 years of learning about synthetic lubricants, what they can and cannot do with real world applications and oil analysis, I am convinced that in sound equipment properly formulated syn-thetic lubricants will last a long time without any mechanical problems. I was a hard sell too. It has to be a money thing as to why extended oil changes are resisted, not a technol-ogy thing. The technology is already here.

Thanks, and keep up the good work.

Gary Thischafer

Midwestern Synthetics

Council Bluffs, Iowa

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