Petroleum Quality Institute of America

The Petroleum Quality Institute of America (PQIA) is an independent resource for information and insights on the quality and performance of lubricants in the marketplace.  Our mission is to serve the consumer of lubricants by reporting on the quality and integrity of lubricants in themarketplace.






DG Auto SAE 10W-40, API SF

Distributed by Dolgencorp, LLC Goodlett, TN

Purchased in: Dollar General, Lugoff, SC

Date of purchase: 12/9/2011




Note: Whereas the results of the tests conducted on this sample meet the requirements of an SAE 10W-40 engine oil, the phosphorus and zinc levels are below what would normally be expected for an API SF engine oil.


API SF is an obsolete specification, and as noted on the back label of this product it should not be used in cars built after 1988.











Test Results

The ranges and averages shown in the table below are for
current specifications (API SN GF-5). See footnote "e"
PHYSICAL TESTS Standard/ranges-b Average-e
 TBN, mg KOH/g, (ASTM D2896) 6.1 to 8.3 7.2 3.5
 Viscosity @ 100ºC, cSt, (ASTM D445) 9.3 to 12.5 10.5 14.1
 Viscosity @ 40ºC, cSt, ASTM D445     90.0
 Viscosity Index (ASTM D2270)     162
 Viscosity @ -25ºC mPa s (cP) (ASTM D5293) 7,000 Max 5,775 4,175
 Volatility, mass % loss, 1 hr, @ 250ºC (ASTM D5800) 15 Max 14.2 17.9
    Nitrogen μg/g (ASTM D-5762) 599 to 990 804.2 349.8
    Calcium  1,570 to 2,460 2,051 991
    Magnesium, ppm  6 to 46 12.3 4
    Phosphorus,  ppm 600 to 800 703 378
    Zinc, ppm  766 to 868 791 404
    Molybdenum,  ppm  <1 to 269 60 20
    Barium, ppm  <1 <1 <1
    Boron,  ppm  <1 to 237 79 20
    Silicon,  ppm-d  3 to 9 5 8
    Potassium, ppm 9 to 17 11 <5
    Manganese, ppm  <1 <1 <1
    Titanium, ppm  <1 to 114 11 <1
    Sulfur, ppm  5,000 max 2,785 2,300
    Copper, ppm  <1  <1 <1
    Sodium, ppm  5 to 454 172 <5
    Vanadium, ppm  <1 <1 <1
    Silver, ppm  <1 <1 <1
    Aluminum, ppm  <1 to 3 1 <1
    Chromium, ppm  <1 <1 <1
    Iron, ppm  <1 to 1 1 <1
    Nickel, ppm  <1 <1 <1
    Lead, ppm  <1 <1 <1
    Antimony, ppm  <1 <1 <1
    Tin, ppm  <1 <1 <1

a- Click here for product label.

b- Standards, shown in yellow are established by API, SAE and others. Ranges, shown in teal, represent the high and low data for the 13 major brands of API SN ILSAC GF-5 tested in September 2011.

c-Test Method for metal analysis is ASTM ASTM D5185.

d- Although silicon is used as an antifoam additive in lubricants, concentrations above 7ppm have been linked to contamination from abrasive material,

e- Average of the 13 major brands of API SN ILSAC GF-5 tested in September 2011.


DG Auto 10W-40
The American Petroleum Institute sets forth a number of laboratory and engine tests required to meet an API SN ILSAC GF-5  performance specification. Although laboratory tests alone cannot be used to establish if an engine oil meets API SN, they can be used to determine if it doesn't.

The following is a comparison of the test results for the sample of DG Auto 10W-40 tested with the API SN ILSAC GF-5 requirements.


The viscometrics meet the required targets for a 10W-40.

Viscosity @ 100șC, cSt, (ASTM D445)
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 Viscosity @ -25șC mPa s (cP) (ASTM D5293)
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Click here for more on chart and Viscosity@100șC,cSt                Click here for about chart and Viscosity @ -30șC


Volatility Phosphorus

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Click here for more on chart and Volatilty Click here for more on chart and phosphorus