In this video we’re going to be talking about why synthetic motor oil is better than conventional motor oil.
And I’m also going to be including a demonstration to help prove some of these points now there’s all kinds of different ways in which you could talk about the differences between synthetic and conventional motor oils but we’re going to be focusing on simply viscosity.
Viscosity is an oils resistance to flow.
So a higher viscosity means more resistance to flow or a thicker oil and a lower viscosity means less resistance to flow.
Or a thinner oil now before understanding the benefits of synthetic motor oils like this Pennzoil Platinum derived from natural gas.
We first need to understand the rating system used for motor oils you’ll often hear 5w30 or 0w 20 as a rating used in cars today.
The first number followed by a W is the cold rating W stands for winter and this means the oil behaves like an SAE 5 grade motor oil while cold but at operating temperatures at about 100 degrees Celsius it operates like an SAE higher than 5.
So it may seem that at higher temperatures the oil is going to be thicker but that’s obviously not the case as things thin out as they heat up and so it’s helpful to look at a plot of kind of what we’re talking about here.
So here we have viscosity thicker at the top thinner at the bottom here we have temperature cold you know around zero degrees Celsius versus hot you know around 100 degrees Celsius.
And so when you’re looking at this if you were to plot an SAE five straight grade oil it would look something like this you know a thinner viscosity than an SAE 30 straight grade oil and then a multi-grade viscosity is going to have properties of both of these.
So at lower temperatures it’s going to act like an SAE 5 oh wait oil but as you can see it’s still going to thin out as it gets to hotter temperatures where it acts like an SI a 30 grade oil.
And so here if it were to just be a 5 it’d be too thin for operating temperature to protect the engine but if it were to operate like an SI 30 I’d be too thick for start-up
And so you have these multi grade characteristics.
So you can kind of have the best of both worlds you can start it up without any issues and you can have plenty of protection once it’s at operating temperature.
So how would you create a multi grade conventional motor oil well you’re going to start with something similar let’s say we’re making a 5w30 you’re going to start with something similar to a straight grade SAE 5 motor oil and then you’re going to have additives which you add to this in order to give it those 5w30 characteristics.
So you can add pour point depressants and what these will do is lower the viscosity at low temperatures and then you can add viscosity index improvers and what these will do is increase the viscosity at high temperatures
And so kind of a way to think about how these viscosity index improvers work you’ve got these polymers that are all balled up when they’re cold and so it’s very easy for them to pass by one another
So you know you’re going to have a low viscosity and then as they heat up they expand out and so they get tangled more easily
And so that increases the viscosity because it’s less easy for them to pass by one another.
So you thicken the oil at high temperatures now of course it’s still thinner than what it will be at at low temperatures but that said it still has a thick enough grade to it that it protects your engine at those higher temperatures now the cool thing about synthetic motor oils is that they already have a multi-grade from the base oil.
So the base oil can be formulated with synthetic motor oils based on the process of creating it.
So that already has this multi-grade characteristic.
And so you don’t have to add as many or any of these you know different additives in order to change the characteristics of its viscosity.
And so what that means is over time it’s going to retain its viscosity grade much better than a conventional motor oil.
So looking at the oil change interval here we have viscosity versus temperature and this is at the beginning of your oil change interval.
So you’ve just changed your oil you’ve got brand new oil in your car this is at the end.
So once you you know you need to change the oil at this point.
And so if you’re looking at conventional versus synthetic originally if you’ve got 5w30 their curves are going to look exactly the same in here.
So here’s that SAE 30 here’s the SAE 5 and you’ve got that exact same curve for both conventional and synthetic but as I mentioned the base oil / synthetic is already that multi grade.
So over time it doesn’t really break down as much you know you are going to have deposits and things like that which are going to get in there and thicken the oil but it’s going to look very similar at the end of your oil change interval versus your conventional is going to get thicker at low temperatures and it’s going to get thinner at high temperatures because these additives have started to break down
And so you’ll get much better protection with synthetic motor oil at the end of your oil change interval if you’re using synthetic than if you were using conventional you’re going to have less protection because it’s thickened at lower temperatures meaning you won’t have as much flow at a cold start and it’s gotten too thin at higher temperatures meaning not enough protection.
And so you know you may be thinking okay well does this mean I can use a synthetic oil for longer oil drain intervals and that’s not necessarily the case at all you should certainly always go with whatever your car manufacturer recommends because there’s all kinds of other additives in these motor oils both synthetic and conventional which I haven’t discussed in this video but anti wear dispersants anti foam detergents rust inhibitors corrosion inhibitors all of these are going to be in both of these motor oils conventional and synthetic and they will wear out over time.
And so for both cases you’re going to need to replace the oil at the same interval you’re just going to have better protection with the synthetic towards the end of your interval than you would with a conventional based on the viscosity differences okay
So now let’s check out a demonstration…
So here we have four heavy-duty engine oil samples all cooled to negative 35 degrees Fahrenheit on the Left we have used and new conventional 15 w 40 and on the right we have new and used in a one full oil drain interval of use synthetic 5w 40 motor oil now at this point you may be thinking wait a minute this isn’t a fair comparison because the synthetic has a lower cold viscosity rating.
So of course it will flow faster at low temps you’re absolutely right however it’s not the main purpose of this demonstration first off formulating a motor oil for 5w 40 rating requires the use of a synthetic base oil as the synthetic base oil is what gives the oil the lower viscosity rating and second and perhaps more important to the viewer is that you can see the difference in viscosity between the used and new synthetic oil is very minimal whereas the difference in viscosity between the used and new conventional is very large.
So what does this mean for the consumer what this demonstrates is that towards the end of your engine oil drain interval for your car if you’re using conventional oil you will have significantly change the viscosity properties of your oil meaning less protection using synthetic however means you’ll retain the viscosity properties of the oil for a longer duration and thus your engine will be better protected towards the end of the oil train interval.