Car Truck SUV Engine Oil Differences Explained

Hey, friends. It's Len here from 1A Auto. Today, we wanted to go over the differences you're going to find when it comes to engine oil. Let's get into it.

Okay. So, just to let you know, this is going to be a super long video. So, grab a snack, grab a drink, and sit down and buckle up buttercup. Here we go. Now, one of the first things that I want to mention right off the bat is that this demonstration isn't supposed to be brand-specific. Yeah, you might see a lot of the same brands, but it's not necessarily about that, it's more just what we had on hand. Now, the first thing that I want to talk to you about are the numbers that you're going to see on every oil jug and that's the viscosity rating. So, now, if you look right down the line, you're going to see all sorts of different numbers on these jugs. And the more you look at them, the more confusing it may seem. Now, we'll go with this one for instance. You're going to see a 5W and then a 30. The reason why this has two is because it's a multi-grade viscosity oil. The reason for that, and the reason why it actually has a W on there is because the first number is the winter weight or the cold weather weight. That's going to be a lower number usually.

And then, of course, when you get to the second number, that's going to be a higher number, and that's when the engine is actually at operating temperature, which is approximately 212 Fahrenheit. You might also see bottles with just one number on it, and that's called straight weight oil. And that's only for specific applications. So, before we get into the differences between viscosity and flow rate, let's continue on with viscosity. If you were to look at this right here, like we were saying before, you're going to have a 5 and then a W and then a 30 on this particular application. Seems a little weird though. Why would it go from being thinner when it's cold to thicker when it's warm? If you were to think about it, what if your vehicle was to start off at like 40 weight oil? Nice and thick, and that's when the engine is cold. It's probably going to have a hard time pushing that oil around. And then as the engine heats up, when it needs more lubricity, the oil is going to be super thin at that point, because if the oil kept getting thinner as they heat it up, that would obviously cause an issue and you would hear engine noise.

Now, is there an oil viscosity that's going to be able to cover all these vehicles? I want to go with no. Each manufacturer is going to have its own oil viscosity rating that they recommended per engine per vehicle. So, now, we're going to compare that to flow rate because viscosity and flow rate are two different things like I said before, and you're not going to find that on this bottle. Flow rate basically comes down to how fast that oil can flow through the system in any given rate of time. So, if you're going by a minute, they need to know exactly how much flow or how much oil is going to be able to flow through that engine, through the filter, and everything per a given amount of time. Continuing on with the front of the bottle, usually kind of near where the oil weight is, you're going to see a little certification right here. And this just says, American Petroleum Institute certifies this for gasoline engines.

Now, if you were to look at the other side of the jug, you're probably going to see another certification, and this one's from the API Service. And what you're going to notice is it has a little letter or a couple little letters. This one says SN Plus. So, now, looking at these letters here, you're going to generally see an S and then a letter following it. The later in the alphabet that that letter is, is the newer that the oil type is. So, it actually started way back in the day with SA and then SB and then so on. Now, we're at the point where it's SN Plus. So, this is pretty much the newest type of oil, and it has the most amount of additives, which is going to be necessary for almost all newer engines.

Now, we have a little chart here that's straight from the API website. So, with that said, if you were to look down here, you can see different age groups of vehicles as they move along throughout history. In older vehicles, they used an SA like I said before, and then SB, SC, and so on up and through the '80s. You know what I mean? You got SE. Anything in red right here is considered obsolete. So, if you've had oil sitting around inside your garage, or up on a shelf inside your shed for a super long period of time, and you happen to pull it off and blow off the dust, and you're like, "Oh, 5-30 oil, this should be fine." Well, no, it's not because it's not up to the rating that newer cars are. Unless, of course, you're working on an older car, in which case, you know, you do you booboo. So, now, as newer cars progressed up and through the 2000s, as you could tell, there's lots of different types of oil grades that were needed.

With that said, to find out the best type of oil to use would be located right inside of your owner's manual. Another possible way you can figure out what your oil viscosity rating should be is right underneath the hood on that oil cap. Now, something you're going to want to pay attention to, especially if you have a GM vehicle is this right down here. It has to say Dexos approved. Dexos oil came out back in approximately 2010, and it was made specifically for GM vehicles. In about 2015, they came out with the second Dexos approval. So, with that said, if you were to get Dexos1 approved oil, and you had a vehicle that's newer than 2015, you're using the wrong oil. If you had a 2014 vehicle and you got the Dexos approved 2, you could use that oil inside that engine, because it has a higher approval rating.

So, now, let's talk about the differences between conventional oil, semi-synthetic oil, and fully-synthetic oil. So now, if we're talking about conventional oil, as the name implies, that's traditional oil. That's the type of oil that they've been using for a long, long time in automobiles and other type of gasoline engines. The reason why it's considered conventional oil is because it was made the conventional way. If you were to move along to synthetic or even semi-synthetic, they had to change that refining process. They had to do a lot more things and add more additives. Conventional oil, of course, would be more suited for older vehicles, which don't necessarily require the latest standards of synthetic oil and such. And something to note would be conventional oil is much cheaper than synthetic oil overall.

But you have to change your oil twice as often. So, now, let's jump right over the semi-synthetic and go right to the full synthetic. Synthetic oil is different than conventional oil because it has to be chemically and physically modified. Now, due to this extra refining process, the oil turns out to be purer and cleaner overall, which, of course, then leads to the fact that you can go a little bit longer on that service interval. But then again, of course, all that extra refining and extra processes and additives are going to make it cost much more than the conventional oil. So, let's slide on back down the chart here, and we're going to go to a semi-synthetic oil now. What's the difference between semi-synthetic oil and the synthetic or even conventional? Well, it's kind of right in the middle, right? Right here. The reason for that is because it's semi-synthetic, it has some synthetic oil in it, and it has some of the regular conventional oil in it. Is it a 50/50 mix? I don't necessarily know exactly how they do it, but they came up with their own reasons for why they did it.

The best thing about it, though, is it kind of gives you the best of both worlds. As newer vehicles progressed, it became more apparent that you needed the use of at least a semi-synthetic oil, but overall, new vehicles or even newer vehicles are going to require full synthetic like I said before. So, now, most of these oils you're going to find are either between 75% and 90% crude oil-based. And then after they've been refined and whatnot, they add those additives and that's going to make up the rest of that 100%. Now, if we're trying to decide between conventional or even synthetic oil to determine approximately how long you can go, well, synthetic oil might last a little bit longer, and that's a proven fact. But you have to start thinking about something else, which would be the filtration for this. Let's say you spend a whole bunch of money on some great synthetic oil because you can't wait to do right by your engine, that's awesome.

But then you go ahead and you buy the cheapest oil filter you can find. Inside that oil filter, you're probably not going to find what you're looking for. It's not going to have the right filtering inside, and it's going to end up breaking down over time, and it's not going to filter the engine oil the way that it needs to, to be able to get out those contaminants. Now, some people have the question, can I switch back and forth between conventional and synthetic oils? The answer, of course, would be, yes. You can do whatever you want. It's your engine. Is it going to cause and effect anything? Well, maybe it will, but more than likely it won't. Would it cause damage? No, it probably isn't gonna cause damage unless you were using synthetic, and you're used to going that 5,000, 7,000, I don't know, 10,000 miles on every oil change interval, and then you switch to the conventional oil, which should have a much smaller service interval, but you continued with that 5,000, 7,000, 10,000-mile interval.

With that said, and like I said before, the longer that that oil is sitting inside the crank case, it's building up more of those gases, it's filling up with even more contaminants from unburnt stuff getting mixed in with the oil. Conventional oil just isn't meant to hold onto that for a super long period of time. So, it's going to cause breakdown inside the engine, that little pitting that I was talking about before. So, to reiterate, synthetic oil does not cause engine noise or engine oil leaks. You'll only probably notice it because of the wear your engine already has. So, now, let's talk about the difference between regular synthetic oil and higher mileage synthetic oil. What's the reasoning for it? It's a great question. With that said, the reason why you'd want to use synthetic oil or even high mileage oil is because as your engine becomes older in miles, I don't want to say age because time doesn't really matter necessarily, the parts are going to become worn. There's going to be larger clearances than what would have normally been inside that vehicle. And like I said before, if you were to use synthetic oil, it's super thin, right? And as the vehicle gets older, those gaskets and stuff are gonna start to get dry and brittle, and the oil is going to try to find its way out anywhere it can. With the high mileage oil, it has special additives in it that are actually going to help those gaskets on the inside of the engine to make it so they kind of re-soften back up, and that's going to help prevent against oil leaks and, of course, engine wear over time.

So, now, another question that you might ask yourself is when should I switch my engine oil over to a high mileage oil? Well, the answer for that would be approximately 75,000 miles. At that point, your engine is completely broken in. Everything's kind of moving the way that it should be. And the tolerances are overall gonna be a little bit more than what they would have normally been. Of course, those seals, they'd be a little bit more worn as well, maybe a little bit dry and brittle. So, you'd switch to the high mileage oil. That's going to have extra additives in there and it's going to help prolong the life of your engine overall. Now, some of the reasons why maybe you'd want to change your oil. Well, over time, the combustion gases inside your engine will sneak past the rings on your pistons, and they'll start to combine with the oil inside the engine. When this happens, the oil inside the engine becomes acidic.

Basically, it's gonna be sulfuric and carbonic acidity. And when that happens, it's going to obviously break down the seals on the inside of the engine, which are very important. And it also has the possibility of actually pitting the inside of your engine. So, now, going over on your oil changes, like I said, you're going to have that acidic oil inside there, and it's going to make those seals dry rotted and brittle. When that happens, you're going to have oil that likes to try to seep out. If you're using conventional oil, overall, it's going to be a little bit thicker than the synthetic oil. Even though maybe you have the same API rating that says 5W-20 or 0W-20. The regular oil or semi-synthetic oil, like I said, is just going to be a little bit thicker and you're not really necessarily going to notice those leaks.

But if you were to go from using regular oil to switching to synthetic, maybe you've got, you know, a 100,000 miles or 150,000 miles, or, you know, a nice older Corolla with 300,000 miles, and you decide that maybe you want to switch to synthetic because you love this car and you want to keep it around for a while, who wouldn't? They're great cars. With that said, what you're probably going to notice is some oil leaks starting. And you're probably even going to notice a little bit of engine noise that maybe you didn't hear before. The reason for the leak would be, of course, those seals are dry and brittle and the thin oil can push right through. It's not necessarily because synthetic oil causes leaks or anything like that, that's very untrue. It just kind of finds those little leaks because it's much thinner.

Now, the reason why I said if you were to switch to the synthetic oil, you'd probably hear engine noise and oil leaks. Well, like I said, if you're using the conventional oil, it's going to dry up those gaskets because it's petroleum-based. When that happens, it's going to cause tiny imperfections, and yeah, maybe the regular oil isn't going to find its way out through there. If you switch to the synthetic, it's going to be thinner. It's going to have a higher flow rate. So, it's going to be able to move easier. It's going to find those tiny little imperfections and it's going to take advantage of that and make its way out of the engine. Now, the reason why you might hear that noise using synthetic oil over the regular semi-synthetic or even basic oil is because of the flow rate. So, the clearances of all those small parts inside of the engine, they're used to having a decent amount of oil that's going in between there causing lubricity and kind of keeping them apart from chattering. If you were to use synthetic, it's much thinner, it's going to make its way through here quicker, faster, and you're going to have those metal parts just kind of making a little bit of noise, like I said, you didn't hear it before because you were using the thicker oil before. And I'm not talking about oil viscosity.

So, now, let's talk about the engine oil pressure. And when I'm talking about that, I want to make sure that you understand that I'm not necessarily talking about the pressure coming directly from that oil pump. A lot of the pressure that you're going to realize either building or not being there is actually due to the fact that the clearances inside the engine are changing over time. That's bound to happen. It's a wear and tear item. Now, when these clearances change, what you're going to happen to notice is probably maybe a little bit of noise coming from the engine, even though maybe you're keeping up with that recommended service interval and you're using the proper oil viscosity. The reason for that is like I said, as those parts wear, the clearances are going to become from being very small and they're going to get larger, of course, it's not going to be on this scale because I can't make them with my hands. You won't be able to see anyway.

As those clearances get larger, the flow of the oil is going to change as well, because it's going to be able to flow right through that big old hole much easier than the small hole, right? With that said, you're going to hear a little bit of engine noise. Another way that that can go is maybe your engine's new or on the newer side, and for some reason, you decided to go with a higher viscosity rating. Maybe your engine is rated for 0W-20 because it's a brand new vehicle and you decide maybe, "I don't want to use 0W-20. Synthetic, it costs me more. I want to go with regular plain old 5-30." Obviously, that's not a great idea. The reason for that is because now that oil is going to have to try harder to squeeze through those low clearance areas inside the engine. So, you're going to have a higher amount of oil pressure. So, now, either of these cases, of course, would be very bad for the engine. And for the purpose of this video, I would only go with the recommendation of your actual vehicle manufacturer, especially if you have a vehicle that has variable valve timing, it could cause detrimental damage to your engine by using the wrong oil viscosity. Do your own research.

So, now, there are four major functions of oil in general. You're going to of course have the lubricating factors, obviously. You're going to have the cleaning factors because inside your engine, it's a very severe environment. There's lots of things going on, there's mechanical parts moving around, and, of course, there's extreme heat. So, there's going to be contaminates that are going to be kind of settling in and you need those to kind of move around. Another purpose of it is to also relieve heat. Inside that engine, like I said, there's a lot of heat. Another thing, of course, it helps with the seals of the engine, helps prevent them from getting dry and brittle and cracking over time.

So, as far as additives, you have detergents, of course, that's going to be the cleaner. There's also going to be a dispersant, that's to help get those contaminants loosened up from clinging to parts and move them around inside the oil. That way there, when you drain out the oil or it's flowing through the filter, it's going to get filtered out. Other than that, you're going to have antioxidants. If the oil oxidizes, you're going to get viscosity increase and probably a little bit more wear. As far as the anti-wear, we also have something that's going to form a chemical layer on metal parts to help reduce that wear. And then, of course, there's a viscosity modifier, which makes the oil thicker with heat rather than the normal thinner when warm. Now, so far, we've been talking about gasoline engine oils. There are other types of engines though, aren't there? You have diesel engines, those type of engines aren't going to use the same type of oil that your gasoline engine is going to use. It's going to be a little bit different. It's going to be refined differently. And more than likely, when you look at those numbers on the front of the bottle, you're going to notice those numbers are much higher. That's because diesel engines tend to run a lot hotter than gasoline engines.

Gasoline engines need three things to run. They need an ignition source. They need air and fuel. With all three of those things, they'll be able to run. Diesel engines necessarily don't need to have an ignition source. The way that they actually run is by compression. And that's because inside of a diesel engine, you have the cylinder, right, and then you have your piston that's going to be coming up. As that piston is coming up, it's creating pressure, pressure, pressure, and it creates so much pressure that it actually spontaneously combusts the air and fuel mixture that's inside of that cylinder, which then drives the piston down, shoots up the next one, which pushes that one up, makes that extreme amount of compression, pooh, comes shooting back down. With that compression, comes a tremendous amount of heat.

So, with that said, would you be able to use a gasoline-rated oil, something like this, you know, 5W-30 inside of a diesel engine? No. Definitely not. You'll end up causing detrimental damage to your engine. And it's not necessarily recommended to go vice versa, by the way. Now, when it comes time to choosing your oil, you're probably going to notice there's a lot of different brands to choose from. They all have their promises. They all tell you what they may or may not do. And that's great. Overall, they all pretty much have the same refining process. The difference would be the amount of additives that they choose to add. So, is it a good idea to switch from different types or different brands? Probably not. Like I said, they make a decision on what type of additives they want to add, and maybe your vehicle's used to one over another. So, keep it as consistent as possible.

So, I know this is a lot of information to try to take in. So, I'm going to try to break it down for you. When it comes to brand of oil, you could pretty much do whatever you want. You do you booboo, pick the one you like and stick with it. When it comes to the viscosity rating or the type of oil, whether it be conventional or synthetic, I would go by the manufacturer's specific recommendation. The reason for that is because they know exactly what type of oil engine should be using. And they're also going to give you a little listing on the interval you should be doing. You want to stick to that interval, and that's going to make sure that your engine lasts for a very long time. So, now, it's going to be super important, and probably the most important is how you dispose of your used oil. It's not just something that you can dispose off willy-nilly. You can't just dump it into the ground or bury it somewhere or put it down the sink, you definitely don't want to put it down a drain of any sort, because it has contaminants and, of course, it can pollute the environment. Nobody wants that. You have to make sure that you recycle it properly, and they're going to take care of all the messy work. So, when you're doing your oil change, it's important to put it inside a nice bucket like this, and then, of course, if you wanted to, you can go ahead and pour it right into the bucket that you got your new oil from.

Okay, friends. So, we tried to make a nice educational video for you about engine oils. Hopefully, you learned a little something. If there's something that I missed or something that you want to talk about, leave it in the comment section below because I'd love to hear from you. If you liked the video, go ahead and smash on that like button for me, it would mean the world. While I've still got you here, go ahead and click on that subscribe button and ring the bell that way there, you can be kept up with all of our latest content. Thanks.
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