الموضوع: ملاحظاتي البسيطة عن الكروز 2014

5W-40 is a disadvantage in any engine. Multi-viscosity oil has viscosity index improvers to make it more resistant to flow when the engine is up to temperature so it acts like a 40 weight oil.

The problem with wide spaced viscosity grades is the following: Polymers are used as viscosity index improvers. After you get 2000 miles on the oil it no longer flows like a 5 Winter grade when the temperature is cold. The more miles you get on the oil the cold viscosity (5W) begins to rise.

The closer the viscosity spread the better.

Who ever dumped that oil in your car should be slapped, with cold weather around the corner.

Over 80% of all engine wear occurs during cold starts. The thinner the oil at low temperatures the faster the oil pump forces a *larger volume of lubricant to all frictional surfaces.




Multi-Viscosity oils are a bit confusing to most people. What your looking at, when you see 5w30, 10w30, etc, doesn't mean anything about temperature.

Here's an example - we'll use 5w30. Which is actually "5 winter 30". At cold temperatures the oil won't thicken up more than straight-5 weight oil, and when hot, the oil won;t thin out more than straight-30 weight oil. The same can be said for the other multi-viscosity oils just using the other numbers instead.



40 menas its thicker at operating temp than a 30. if you use a 40 weight in an engine that calls for a 30. you can ruin your engine as the thicker oil cant get to all the places in the engine that it should. so use what the car calls for.