Mak­ing sense of all those letters and num­bers

Motor Equipment News - - NEWS - Supplied by eni lu­bri­cants.

Pick up any pack of oil and read the la­bel. Printed there will be a se­ries of ab­bre­vi­a­tions that tell you the per­for­mance at­tributes of the pack’s mys­te­ri­ous, brown slip­pery con­tents.

API (Amer­i­can Petroleum In­sti­tute) spec­i­fi­ca­tions are per­haps the most widely quoted. Prior to 1930, the API in­tro­duced a sys­tem of en­gine oil spec­i­fi­ca­tions. “S” de­noted a petrol en­gine (think spark) and “C” de­noted a diesel en­gine (think com­pres­sion) fol­lowed by a sec­ond let­ter. As the sec­ond let­ter ad­vances along the al­pha­bet, so too do the per­for­mance re­quire­ments. API SA was the first and has pro­gressed to API SN, in­tro­duced in 2011.

The ta­ble be­low lists the year pro­gres­sive API stan­dards were in­tro­duced. The bot­tom row lists the power out­put of the six-cylin­der four-litre Ford Fal­con en­gine. This en­gine con­fig­u­ra­tion was rel­a­tively un­changed, but power out­put in­creased by over 50 per­cent.

In 1972, oil drain in­ter­vals were 2,500 miles (4,000km), and ev­ery petrol sta­tion had an oil bowser in the fore­court. In the fol­low­ing years, emis­sion con­trols tight­ened, and ex­haust gas re­cir­cu­la­tion was in­tro­duced.

This meant higher tem­per­a­tures and more ex­haust gases for the en­gine and its oil to cope with. En­gine de­signs changed, drain in­ter­vals ex­tended, and sump sizes got smaller. The API sys­tem pro­vided a per­for­mance stan­dard that en­gine and lu­bri­cant man­u­fac­tur­ers could use as a base­line.

ACEA – As­so­ci­a­tion des Con­struc­teurs Eu­ropéens d’Au­to­mo­biles – is the Euro­pean sys­tem for lu­bri­cant clas­si­fi­ca­tion. It uses a com­bi­na­tion of letters and num­bers to des­ig­nate ap­pli­ca­tion and per­for­mance level.

En­gine type fol­lowed by Tech­ni­cal Per­for­mance Level 1, 2, 3, 4, 5, 7, 9. A: Petrol. B: Light diesel. E: Heavy duty diesel. C: Cat­a­lyst com­pat­i­ble oil. Stated ACEA spec­i­fi­ca­tions of­ten in­clude more than one des­ig­na­tion. As an ex­am­ple ACEA A3/B4 is a spec­i­fi­ca­tion for a petrol and a light diesel en­gine. Tech­ni­cal per­for­mance level does not nec­es­sar­ily in­crease with the higher num­ber. ACEA A1/B1 has bet­ter fuel sav­ing per­for­mance than ACEA A3/B4, but the lat­ter has ex­tended drain ca­pa­bil­i­ties.

On top of API and ACEA spec­i­fi­ca­tions will be OEM stan­dards. These are the most im­por­tant if you want the cor­rect lu­bri­cant for your ve­hi­cle. How­ever, not all OEM’s have lu­bri­cant stan­dards but will in­stead spec­ify that a lu­bri­cant must meet a cer­tain API or ACEA stan­dard.

A typ­i­cal ex­am­ple of the spec­i­fi­ca­tions listed on a pack is those on eni i-Sint CRDI 5W-40. It states ACEA, Amer­i­can Petroleum In­sti­tute and spe­cific OEM stan­dards for BMW, Mercedes-Benz, Volk­swa­gen and Porsche. All rep­utable lu­bri­cant man­u­fac­tur­ers will state the stan­dards that their prod­ucts meet in a for­mat sim­i­lar to this.

As you have seen, there is a method to the mad­ness. Un­der­stand­ing and ap­pre­ci­at­ing what these num­bers and letters are telling you are the key to en­sur­ing the cor­rect oil is used in the cor­rect ap­pli­ca­tion.

For fur­ther in­for­ma­tion on eni lu­bri­cants visit: www.tran­sdiesel.com

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