Thread: OIL

The 5 in the 5W40 is the cold viscosity rating for the engine oil and it represents the oil thickness during cold weather. 5 weight oil is thinner in freezing temperatures than 15 weight oil and therefore lubricates faster during startup and run of the cold engine. It also gives less resistance and therefore better economy which is probably neglible though. However after the engine reaches operating temperature its irrelevant I would think I...

i was told that i should used 15w40 oil in my td5,however when i when for a new rotor filter my supplier asked what is was using and i told the i was using 15w40.they said that i should be being using 5w40 oil,so i made the switch.i have notice something,once before when i had in the 15w40 oil,when i am on the highway and driving it hard,the speed would be 130ish and i can hear and feel the rpms high,but now i am get up to same speed,but the...

5W is thinner than 15W , SO the viscosity of the oils will lower when heated up.... bearings have the smallest possible clearance's , which one do you think will be able to get in there faster ???? to lubricate, more lubrication = quieter engine. + less friction, resulting .........(long term) longer engine life...........