Ib qhov oil viscometer yog ib qhov khoom uas pab paub tias ib qhov dej yog loj lossis nyooj li cas. Qhov no yog qhov txaus tshwj xeeb rau ntau yam feem, tias yuav tsum tau hais rau kev tsim kho tsev. Piv txwv li, lub oil yuav tsum muaj qhov viscosity tswv yim rau kev ua haujlwm zoo rau hauv cov khoom thiab cov engine. Thaum lub oil yog loj heev, nws tsis tuaj yeem hloov hloov zoo; thaum nws nyooj heev, muaj kev noj qab tias nws yuav tsis tuaj yeem npog cov khoom uas nws yuav tsum npog. Lub oil Viscometers yuav pab cov laus kho rau kom paub tias cov khoom uas lawv tsim yog safe thiab muaj kev ua haujlwm zoo.