Vis­cos­ity

Car Mechanics (UK) - - Engine Oil & Lubrication -

The thick­ness of oil is crit­i­cal to en­gine pro­tec­tion. It must be thin enough to reach crit­i­cal parts as soon as pos­si­ble after a cold start, yet re­tain suf­fi­cient body to pro­vide a pro­tec­tive film of oil between mov­ing parts when hot.

Mod­ern en­gine de­sign and de­creas­ing tol­er­ances have re­sulted in thin­ner oils that cause less drag, in­creas­ing ef­fi­ciency but re­duc­ing CO2 emis­sions and fuel con­sump­tion. Es­tab­lished by the So­ci­ety of Au­to­mo­tive En­gi­neers, the first num­ber on mod­ern multi­grade oils that is fol­lowed by the let­ter ‘W’ is the 'win­ter' ref­er­ence, when the oil is cold, fol­lowed by a ‘hot’ ref­er­ence, which is mea­sured in cen­tis­tokes at 100°C.

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.