Choosing Engine Oil

Uploaded by repairs101ca on 31.07.2011

Today on Repairs101 Iím going to show you how to choose the right engine oil for your
vehicle. Alright, here we go. Today on Repairs101 I
thought Iíd try and answer the question that I get asked more than any other question - and
that is ìWhat kind of oil should I put in my engine?î Now itís a really good question
and itís really worth looking into. So today I thought I would try and teach you how to
decide for yourself what kind of engine oil to put in your engine. Using the wrong motor
oil can lead to poor performance, premature wear and ultimately it could lead to failure.
Hereís the chart given in my Buick Centuryís ownerís manual. You can see, very similar
in the ownerís manual for my Blazer. So maybe the first question youíve got to
ask yourself is ìWhat am I burning? Am I burning gas or diesel?î Thereís a big difference
between oils designed for gasoline engines and oils designed for diesel engines.
So the API ñ the American Petroleum Institute is the system thatís in use here in Canada
and the US. So the API classifications start off as SA, then SB, SC, SDÖ you get the idea,
right? Around the world there are other systems in use. OK you can see here right in the opening
pages of the book ñ of the service manual - you can see that they are telling you that
they want engine oils that are labelled by the API.
OK so they call this ìthe API Gasoline Engines Starburstî. Oils made specifically and exclusively
for gasoline engines will have the starburst on them.
OK now this little symbol here is called ìthe API Donutî and this donut gives you all the
information you need to know about the oil. It says that itís API service SL, in the
middle of the donut it says that itís SAE 5W-30 viscosity and underneath it tells you
that itís an energy conserving oil. Hereís a list of API Service Classifications
for gasoline engines and hereís a list of API Service Classifications for diesel engines.
Now, of course the reason Iím flashing through this quickly is because, for most people,
itís really not that important. A real Gearhead might want to study these charts and understand
them. Now most people just arenít going to need to know every service classification
on the chart, OK? Weíre going to go to the store weíre going to pick up whatís on the
shelf. Itís going to be fairly current if not the most current oil available and itís
going to match our fairly new to used vehicles. Whether you think the ìSî is for ìSparkî
or ìServiceî and whether you think the ìCî is for ìCompressionî or ìCommercialî ñ
it doesnít matter, as long as you learn that ìCî is for diesel burning engines and ìSî
is for gasoline burning engines. If you have a brand new vehicle I definitely recommend
checking and seeing that the Service Classification called for by the engine manufacturer matches
the service classification of the engine oil you intend to use.
OK so viscosity ñ now thatís another issue. Viscosity is the measure of how thick an oil
is. Think of molasses in February, now thatís going to be really thick. Right? Whereas water
is thin. The lower the number on the viscosity scale ñ the thinner it is. So itís very
simple. So a five weight oil is going to be very thin compared to a forty weight oil,
say. So keep in mind that when youíre considering viscosity for your vehicle, really what youíre
asking yourself is ìIs it going to be thin enough to start in the coldest conditions
that itís going to be exposed to?î So for instance, if youíre in the Yukon at Christmastime
youíre going to need thin oil ñ you know a five weight oil or even a zero weight oil.
If youíre in an Equatorial climate then for sure youíre not going to really need anything
very thin. You could go with a straight forty weight oil or straight thirty weight oil probably
and have no problems ever starting it because itís not going to be thickening in the cold.
So Multi-grade oil is what theyíve come up with to address the problem of ìcold startsî
and then being thick enough to protect the engine when itís hot and running. When itís
cold it behaves differently than it behaves when itís hot and the way they do that is
they introduce a polymer into the oil in order to make it behave differently at different
temperature ranges. For instance, when itís cold it will be much thinner than when itís
hot. Which is counter-intuitive, I understand. So what theyíre saying here is if itís below
zero degrees Fahrenheit youíre going to need a 5W-30 oil and if itís above zero degrees
Fahrenheit youíre going to be OK with a 10W-30 multi-grade oil. OK over on this page weíve
got another viscosity chart and this time itís given like a bar-graph.
So most everybody uses multi-grade oils in the vehicles these days with the exception
of ìextreme serviceî and collectors you know, the real hardcore Gearheads, theyíre
going to want to use single weight oils because theyíre changing their oil three and four
times a year and they want to make sure that ñ no matter what the conditions are - theyíve
got the absolute best performing oil in their crankcase. Most people are going to fall into
the lower one or two of these categories and be wanting to use either single-weight oils
from this column here or multi-grade oils here and here, OK?
Compared to conventional oils, synthetic oils last a lot longer, they can withstand a lot
more heavy duty applications, extreme duty applications, more continuous service. Theyíre
better in turbo-charged systems, super-charged systems ñ anywhere again where there is extreme
service. OK some examples of extreme service would be ñ continuous service. Say an engine
thatís running twenty-four hours a day like a Taxicab or a Police vehicle. Say a forklift
thatís running commercial duty. Race-cars, high performance vehicles, or how about say
a tugboat thatís running twenty-four hours a day pulling a load through the inside passage.
Something like that, you know? Thatís extreme service.
Now synthetic oils will last longer because they resist degradation through oxidization.
In other words they donít oxidize quite as rapidly as conventional oils.
OK so after you decide what youíre burning ñ gas or diesel ñ and which Service Classification
of oil you need ñ is it a ìCî class oil or an ìSî class oil? Then the last thing
you want to know is what viscosity you want and the only thing you have to ask yourself
is ìHow cold is it going to get when I start this thing?î And, like I said, the lower
the temperature, the lower the number viscosity you want. And if itís real, real cold out
there you want something as low as 5W or even 0W to get her started.