Why isn't 5w20 good for long trips? Does it get as hot as 10w30?
If it were truly the best choice, I don't feel that they would have to make rules like that... Not saying it's not good, just not best.quote:
EPA will approve the use of a GF-3 oil in test vehicles if the following conditions are satisfied:
1. Owner’s Manual Language. The manufacturer provides clear and unambiguous instructions in
the Owner’s Manual which identifying GF-3 non-synthetic engine oil of a specific viscosity grade
(e.g., 5W20, 5W30, 10W30) as the engine oil to be used under ambient temperature conditions likely
to be experienced during normal vehicle operation. It is appropriate for a manufacturer to specify the
use of a lower viscosity engine oil in extremely low ambient temperatures where the normally
specified oil may not flow adequately.
2. Labeling the Oil Filler Cap. The manufacturer clearly indicates on the engine oil filler cap, by
label or other permanently attached means, that GF-3 oil of a specific viscosity grade (e.g. GF-3
5W20) is to be used in the engine.
3. Limits on the Sum of 16-hour plus 96-hour Fuel Economy Improvement Factors. The engine oil
to be used in emissions and fuel economy test vehicles must have a combined fuel economy
improvement factor (using the ASTM Sequence VI-B (or its replacement procedure)) which does
not exceed the following limits:
GF-3 5W20 4.2%
GF-3 5W30 3.4%
GF-3 10W30 2.0%
The limits were calculated as the sum of the 16-hour and 96-hour limits plus 0.5 percent. The 0.5
percent was represented by the Alliance as covering about two standard deviations of the distribution
of fuel economy improvement rates measured by the ASTM procedures. EPA is setting these limits
because it is inappropriate for a manufacturer to select a significantly better oil for fuel economy
testing than the typical customer will be using in their vehicles.
4. Factory Fill Oil Requirements. The manufacturer uses GF-3 oil of the same viscosity rating as
factory fill in production vehicles. Furthermore, the fuel economy performance of the oils used as
factory fill must be equivalent or superior to the oils used in emission and fuel economy test vehicles.
5. Oils Available at Dealerships. The manufacturer supplies its dealers with GF-3 oils of the same
viscosity grade as used in the test vehicles or otherwise assures the use of the appropriate viscosity
grade GF-3 engine oil at dealerships. Furthermore, the fuel economy performance of the oils
supplied to dealers must be equivalent or superior to the oils used in emission and fuel economy test
vehicles.
1. Instructions to“Quick Change” Facilities and the Manufacturer’s Dealers to use 5W20 GF-3 Oils.
The manufacturer commits to do the following shortly after the start of the applicable model year:
a. Acquire from oil manufacturers and supply to EPA copies of materials that they supplied
to "quick oil change" facilities pertaining to the use of 5W20 GF-3 engine oil.
b. Provide EPA with copies of materials that the manufacturer sent to its dealers pertaining
to the use of 5W20 GF-3 engine oil in customer vehicles.
2. Follow-up Survey of 5W20 Oil Usage. The manufacturer commits to perform the following
either approximately two years after the use of 5W20 engine oil is approved by EPA, or immediately
prior to applying for 2004 model year certification:
a. Acquire from oil manufacturers and provide to EPA sales data of 5W20 and at least the
two highest-selling oils by viscosity grade (other than 5W20), promotional information
applicable to the use of 5W20 engine oil, and follow up letters of commitment for the
continued promotion of 5W20 engine oil; and
b. Acquire from oil manufacturers and provide to EPA the fuel efficiency data of their 5W20
and the highest-selling oils identified in a. above, relative to the reference oil as specified
in ASTM Sequence VI-B (or its replacement procedure). This information may be collected
and reported to EPA in conjunction with other vehicle manufacturers; and
c. Acquire and provide to EPA data on the retail prices of 5W20 and the highest selling oils
identified in a. above. Prices of non-synthetic, partial synthetic and synthetic oils are to be
included. This information may be collected and reported to EPA in conjunction with other
vehicle manufacturers.
This information will be used by EPA to determine whether approval of the use of 5W20 engine oil
should be extended beyond the 2003 model year.
First, 100°C is an arbitrarily low number. Recall that the Sequence IIIG test runs at 150°C for 100 hours. 120°C might be a more realistic crossover point.quote:
Originally posted by Winston:
How about this simple argument.
5W20 is best if you do short trips, and/or you drive in a way where your oil never gets overly heated.
10W30 or thicker is better if you drive in such a way that your oil is often over 100C.
Thus, 5W20 is best for most drivers.
Respectfully, this is not true. The first number represents a viscosity of the oil at -35 degF. At those very, very cold temps your startup argument is true. However, most people start their engines at temps above 30-40F. (of course there are a million exceptions) At the 30 to 40F temps, most 5W20's will be thinner than most 0W30's. So, at the typical startup temp, 5W20 oil will be thinner than ANY Xw30 oil.quote:
At cold startup, generally (basestock, syn oil, etc. excluded), any 0w- oil should flow better than any 5w- oil, which should flow better than any 10w- which is better than the 15w- oils. Of course, at ones' own strting temp, this may not be entirely true as it is not a linear argument.
Pure conjecture on your part. I think it has more to do with consumer culture and mindset than forcing manufacturers into using inferior products. The EPA simply wants to insure that manufacurers don't use a "slick" oil for EPA testing while there is no infrastructure to support the use of these oils and the education of the public of the new requirements.quote:
Originally posted by VaderSS:
If it were truly the best choice, I don't feel that they would have to make rules like that... Not saying it's not good, just not best.
Agreed, thus why I made mention of the nonlinearity of the various results. However, -35 is only the testing point for one specific viscosity number, not all 0, 5, 10, 15's, etc. Without the temperature/viscosity curves for a definitive sampling of the typical oils most commonly used (which is what would be necessary to tailor an oil choice), I can not say for certain.quote:
Originally posted by Winston:
Respectfully, this is not true. The first number represents a viscosity of the oil at -35 degF. At those very, very cold temps your startup argument is true. However, most people start their engines at temps above 30-40F. (of course there are a million exceptions) At the 30 to 40F temps, most 5W20's will be thinner than most 0W30's. So, at the typical startup temp, 5W20 oil will be thinner than ANY Xw30 oil.quote:
At cold startup, generally (basestock, syn oil, etc. excluded), any 0w- oil should flow better than any 5w- oil, which should flow better than any 10w- which is better than the 15w- oils. Of course, at ones' own strting temp, this may not be entirely true as it is not a linear argument.
One example. GC 0W30 is thicker at EVERY temp than M1 5W30 (the newer thicker SM version)-20degF. It doesnt behave thinner until -20F.
I think this is one of the most misinterpreted numbers on BITOG.(the first number in the oil weight designation)
The viscosity chart you showed us says 5W20 will provide optimal fuel efficiency. It makes no mention that 5W40 (or the other grades) will necessairly provide better protection. Show me where on the chart does it say grades other than 5W20 will provide better protection. You're the one who is assuming that grades other than 5W20 will provide better protection.quote:
HOWEVER, 5W-40 for example will provide better protection (as indicated by the Japanese manual for example)
To this point, there is no evidence (other than your speculation) that an engine won't last for 400K worth of hard driven miles on a 5w-20. OTOH, you'll probably be on your third transmission by 400K anyway, considering that most newer automatic transmissions (if you have one) last about 150,000 miles before they have some solenoid, valve body, or electronic failure.quote:
You can't "pick and chose" and base your argument on few UOAs. I will repeat, will keep my Honda engine run for 100-150k miles. However, what about 400k hard driven miles? 20 weights? I don't think so.