Hello, and welcome to Simplified on PowerDrift where we take complicated automotive ideas and
break them down into something you can use. If you haven't, this would be a good time to
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And that's more or less what we're talking about today, cooling systems in terms of
air cooling, oil cooling and liquid cooling, and what you need to know before you make a decision
about them. Now, if you're buying a car, you don't have to make a decision anymore, because most cars
today are 100% liquid cooled, there's just no getting away from it at all and there's no reason
why you should even think about it. On motorcycles though, the engines are out there and we still
have air cooled engines, oil cooled engines and liquid cooled engines and we get a lot of
questions saying that this particular motorcycle is air cooled, it competes with this motorcycle,
which is liquid cooled, and how should I decide? And the simple answer to that is
you don't need to think about the cooling system when you're purchasing the motorcycle, it's baked
into the system, it has a job to do, and it doesn't really affect you in any serious way.
Now, some people will say that air cooled engines feel hotter to ride when you're
riding them and that's not actually true. If you think about it, a Harley Davidson V-twin
is air cooled most of the time, a Ducati V-twin will be liquid cooled most of the time, both of
them places cylinder between your legs very, very close to your thighs in the middle here
and what that means is, no matter how you ride it, there is a source of heat placed very close
to your legs and that will always be slightly uncomfortable, there's just no getting away
from it. The way that the engine is cooled, honestly, has nothing to do with this.
Now, air cooled engines are generally the oldest form of cooling that we've used and the cooling
system you've to remember is designed to make the engine run at an optimum temperature,
it doesn't do anything for the rider per se, that's not what the design is aimed at
Air cooled systems are very simple to understand because what they do is they use
fins and the fins essentially increase the surface area of the engine on which the air can run and
take away more heat. The running of the air is crucial to air cooling because what you should
know is for example, if you burn your hand, the doctors will not tell you to put your hand in cold
water as much as put it in running water because running water is 80% more efficient and carrying
heat away than standing water and in the same way, an air-cooled engine just sitting there in
the heat with no wind flowing over the fins is not really doing a very good job of cooling itself.
That said, this is also accounted for by the manufacturer. So I've never actually seen a
air-cooled engine shut down in the heat simply because it failed to cool itself, even in the
hottest temperatures that you can imagine. All of this is tested and therefore you don't really need
to worry about it. Oil cooling is a halfway house where there is somewhat of air cooling happening,
but the manufacturer decides that the engine is making so much heat and remember, there is
another Simplified if you haven't seen it, go see it, we'll leave a link for you in the description,
where we talk about how internal combustion engines basically run on heat, they don't run on petrol,
they don't run on diesel, they use petrol and diesel to create heat which actually creates
movement. Now, if the heat is too much, and an air-cooled system can't handle it,
the simpler way to do cooling then is, oil cooling and what oil cooling system does,
is it adds a radiator to the system, the radiator's obviously connected to the system,
so hot oil can go in on one end, come out the other end and the cooling of the oil adds an additional
cooling component. So there is some amount of air cooling and some amount of oil cooling going on.
Again, the idea is to cool the engine down, it has nothing to do with you, the rider.
Liquid cooling systems are technically the latest of these three to arrive on the scene and they are
the most complicated system to build because the engine has to have internal channels through which
the coolant can circulate. So this is a part of the design of the engine itself. Then there
is the hosing and all of the connections that require this coolant to go to the radiator,
so the radiator has a hot side from where hot coolant will enter and a cold side where the
cold coolant will leave and then there is a pump that pumps the whole thing through and a
thermostat which is the most important part of the system in the sense that it controls
what happens to the coolant's temperature. So when the coolant is too cold, it can bypass
the radiator so we don't cool it too much and when the coolant is hot enough then it ensures that
the radiator is used so that you have cold coolant running through the engine absorbing all the heat.
But, as a user, none of these three systems should make any difference to you. The biggest advantage
of liquid cooling is the fact that, in theory, once a manufacturer adds fans to the radiator,
the cooling continues once you've stopped and two, there is the opportunity to direct the hot air
that comes out of the radiator away from you, but a lot of manufacturers are only able to do this
if the machine is fully faired or has a substantial amount of body work in the area. If you're riding
a naked liquid cooled machines, honestly, the manufacturer can't do much to control where the
air goes as it comes out hot from the radiator, so you're still going to be suffering from the heat.
In terms of simplicity, obviously the air cooled system is the simplest and the most
self-contained. There are no moving parts, it always works as long as the breeze is moving, the
engine will continue to cool. Oil cooling systems, slightly more complicated, but the radiators are
relatively smaller, the hosing and plumbing is relatively small, so it's a much simpler system
to use, but obviously, now you have dependencies if the oil is low, the radiators blocked, you're
not moving, that isn't a fan on this heatsink, you're going to be in a little bit of trouble.
Liquid cooling systems are considered the most efficient systems, that's why they appear on all
the performance machines, but they're also the system with the most moving parts and that means
that is where things get complicated. So if you have a radiator hose pipe leak,
that's something to fix, if you're radiator breaks or has a hole because a stone went through it,
that's a problem, if your water pump fails, then that's no longer coolant circulating through it
and of course, you have to keep an eye on the coolant level and age.
Age is important because green coloured coolants generally lasts about two to three years, whereas
pink coloured or red coloured coolants last up to five years and this is primarily because the
properties of the anti-freeze and anti-rust agents in there deteriorate over time and that's why
it's important that you change your coolant so that system can run as efficiently as possible.
But to answer the question, in the simplest terms, the question you ask us most often
is should I be looking for an air-cooled engine or a liquid cooled engine, I'm saying look for a
motorcycle that makes you happy, that's far more important than what cooling system it uses.
The cooling system is designed to handle extreme low and extreme high temperatures by the manufacturer.
Most serious manufacturers will do extensive validation and verification to ensure that the
system can do its job efficiently, so all you have to do is focus on the sensations you're getting,
and get the best motorcycle you can. Thank you so much for watching, this is Simplified
on PowerDrift where we take complicated ideas and break them down into really small parts.
If you'd like us to talk about a cooling system in detail, for example, how does liquid cooling work?
Leave us a comment and if there's other topics that you'd like to see on Simplified,
all you have to do is just tell us here and we'll get right on it.
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