We all know that one of the most important things that we can do to an engine to make it last a long time is to change the oil. But, how many people really understand what oil does in an engine? See, back in the day, engines were a lot less complicated than they are today. You look at a modern engine and oil has to do a lot of different things.

Number 1, of course it lubricates. But today with variable valve timing and different controls like that, the oil has to have a proper pressure to make all of these things work correctly. But the other thing, the really big thing that oil does, is that it is a coolant. Down at the bottom of the engine you can’t have the coolant from the radiator down here where the oil is. It can’t mix together, that would destroy the engine. So, all of these lubricated parts inside the engine, they all get hot due to friction and other combustion gasses and all that stuff. It gets very hot. It is the job of the oil to keep those parts cool.

Now, in order to do that, the oil flow has to be proper. Now again back in the day, engines were not computer designed. They weren’t computer manufactured. So the tolerances inside them were not as precise as they are today. The distance between the moving parts, the oil has to flow through and fill the gap, it wasn’t as tight as it was today. So that means, back in the day when you could have thick oil in the car, something like we have right here. This, we can see is quite thick. Alright.

Well today we might use something that is, like this, much thinner. And the reason why it’s thinner is because the gaps that it has to flow through are smaller. And it has to flow through there at the proper rate, number 1 to make all of the computer controlled devices work properly and number 2, at the proper rate so it can absorb heat to keep the bearings and parts from burning up.

So, always make sure that you use what the manufacturer recommends as far as the oil viscosity goes. Thicker is not better. And if you have a question or comment, drop me a line right here at MotorWeek.