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 the marketplace.





Castrol GTX 5W-30 (December 2009)-a




PHYSICAL TESTS Standard/ranges-b Average-e Castrol 5W-30
 TBN, mg KOH/g, (ASTM D2896) 7.4 to 9.0 8.0 8.4
 Viscosity @ 100ºC, cSt, (ASTM D445) 9.3 to 12.5 10.39 10.32
 Viscosity @ 40ºC, cSt, ASTM D445 55.0 to 82.0 60.48 59.26
 Viscosity Index (ASTM D2270) 156 to 167 163 165
 Viscosity @ -30ºC mPa s (cP) (ASTM D5293) 6,600 Max 5,793 6,220
 Volatility, mass % loss, 1 hr, @ 250ºC (ASTM D5800) 15 Max 13.5 13.2
    Nitrogen μg/g (ASTM D-5762) 720 to 1,000 860 720
    Calcium  1,648 to 2,301 2,043 2,189
    Magnesium, ppm  6 to 43 11 8
    Phosphorus,  ppm 600 to 800 772 717
    Zinc, ppm  789 to 887 851 789
    Molybdenum,  ppm  <1 to 226 93 <1
    Barium, ppm  <1 <1 <1
Additive and/or other
    Boron,  ppm  <1 to 246 84 <1
    Silicon,  ppm-d  4 to 8 5 8
    Potassium, ppm  <1  <1 <1
    Manganese, ppm  <1 to 8 1 8
    Titanium, ppm  <1 <1 <1
    Sulfur, ppm  5,000 max 3,021 2,698
    Copper, ppm  <1  <1 <1
    Sodium, ppm  <1 to 467 82 357
    Vanadium, ppm  <1 <1 <1
    Silver, ppm  <1 <1 <1
    Aluminum, ppm  <1 to 2 <1 2
    Chromium, ppm  <1 <1 <1
    Iron, ppm  <1 to 1 1 1
    Nickel, ppm  <1 <1 <1
    Lead, ppm  <1 to 1 <1 <1
    Antimony, ppm  <1 <1 <1
    Tin, ppm  4 to 5 5 5

a- Click here for product label.

b- Standards, shown in orange, are established by API, SAE and others. Ranges, shown in teal, represent the high and low data for the majors shown.

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 10 major brands tested. Click here for brands tested.

Castrol GTX 5W-30 (December 2009)
The American Petroleum Institute sets forth a number of laboratory and engine tests required to meet an API SM performance specification. Although laboratory tests alone cannot be used to establish if an engine oil meets API SM, they can be used to determine if it doesn't.

What follows is a comparison of the test results for Castrol GTX 5W-30 as compared to the API SM requirements.

The API limits for each test are shown by the yellow bars. The test result for Castrol GTX 5W-30 are illustrated by the horizontal line.

The viscometrics of Castrol GTX 5W-30 meets the required targets for a 5W-30 API SM (SAE J300 specification).

Volatility Phosphorus
The volatility of Castrol GTX 5W-30 is within the parameters required for an API SM GF-4 designation.

The phosphorus content in Castrol GTX 5W-30 is within the parameters required for an API SM GF-4 designation.




Click here for Castrol's info on its 5W-30 Note: This link takes users outside of the Petroleum Quality Institute of America website. PQIA is not responsible for the content shown at the link, nor does it endorse or otherwise represent the product statements shown at the Castrol website or associated links.