JASO Classifications


The performance level of two-cycle oils is classified into three grades FB, FC and FD according to test results in four engine tests (a lubricity test, a detergency test, a smoke test and an exhaust system blocking test); and three properties (kinematic viscosity at 100°C, flash point and sulfated ash).
FA was an earlier classification that is now obsolete.

FB is the base grade.
FC is superior to FB in exhaust smoke and exhaust system blocking.
FD is superior to FC in high-temperature detergency.


Oils are classified into four grades (MA, MA1, MA2, MB) according to their performance in a clutch friction test. Additionally, oils must meet one of the following performance categories: API SG, SH, SJ, SL, SM, SN, or ILSAC GF-1, GF-2, GF-3, ACEA A1/B1, A3/B3, A3/B4, A5/B5, C2, C3, C4 and must meet certain limits on sulfated ash, phosphorus content, evaporative loss, foaming, shear stability and high‑temperature/high‑shear viscosity.


The JASO DH-1, DH-2 and DL-1 categories are defined in the Automotive Diesel Engine Oil Standard “JASO M 355: 2008“.
The JASO DH-1 category was developed for 4-stroke automotive diesel engines subject to the Japanese long-term exhaust emission regulations. The DH-1 classification stipulates wear prevention, corrosion prevention, high-temperature oxidation stability, and soot control, etc. DH-1 oils are targeted at the suppression of deterioration of piston detergency, formation of deposits at high‑temperature, foaming, oil consumption due to evaporative loss, viscosity decrease by shear, deterioration of oil seals, etc. Such oils may also be used in engines which predate the Japanese long-term exhaust emission regulations. When the appropriate engine manufacturers’ recommendations on drain interval are followed, DH-1 oils may be used with fuel in excess of 500 ppm sulfur.
The JASO DH-2 and JASO DL-1 classifications were developed for 4-stroke automotive diesel engines equipped with after-treatment devices such as diesel particulate filters (DPFs) and catalysts in compliance with exhaust emission regulations subsequent to the Japanese new short-term regulations. DH-2 and DL-1 oils are eminently suitable for DPF and catalyst equipped vehicles and provide the same performance level as the DH-1 classification.
Because the requirements of trucks and buses differ from those of passenger cars in engine durability, service interval, fuel economy, etc., the DH-2 classification was designed for heavy-duty use by trucks and buses while the DL-1 classification was designed for light-duty use by passenger cars.
DH-2 and DL-1 oils are recommended only where fuel sulfur is < 50 ppm. Where such fuel is used and engine manufacturer oil change intervals are followed, DH-2 oils may also be used in engines predating the Japanese new short-term exhaust emission regulations.
More information is available at http://www.jalos.or.jp/onfile/jaso_e.htm