Turning engine off when it's hot

[snowmannn]

Hi guys,

I've noticed that when I turn off the engine while it's hot (dashboard shows 100+ degrees Celsius) and the fan is working, the fan stops. But if I then turn the key back to ON without starting the engine, the fan starts working again until the temperature drops to ~95 degrees Celsius.

So I wonder what's the right thing to do when the engine is hot and the fan is spinning:
a) wait for the fan to stop /temp goes down/ before turning the engine off;
b) turn off the engine but leave the key to ON so that the fan cools the engine;
c) just turn off the engine and worry no more.

What do you think?

Thanks

 

[GConn]

I certainly don't know what's the RIGHT thing to do....but I wouldn't think it would matter too much for the engine. When I stop I turn the switch to off. The bike cools down on its own. I don't know how much wattage the fan needs to work, so I rather turn it off and save the battery.

But let the experts chime in and educate us on the right thing to do (if it makes any differesnce at all).

 

[Nelly]

I certainly don't know what's the RIGHT thing to do....but I wouldn't think it would matter too much for the engine. When I stop I turn the switch to off. The bike cools down on its own. I don't know how much wattage the fan needs to work, so I rather turn it off and save the battery.

But let the experts chime in and educate us on the right thing to do (if it makes any differesnce at all).

Hi Mate,

I am not sure about your question, I have only had my fan run once when I was sat in traffic. The air temp was 86C. When my engine was off the fan also stopped. I will need to check the manual to see what it says. Also if I am correct the temperature is taken from the air inlet so may not directly corrolate to the true engine temperature.

Nelly

 

[BranNwebster]

You might as well shut her completely down because all the fan is doing is cooling the radiator and draining your battery, ain't no water circulating if the engine isn't running.

 

[reiobard]

You might as well shut her completely down because all the fan is doing is cooling the radiator and draining your battery, ain't no water circulating if the engine isn't running.

I have noticed the same thing and sometimes if i am not in a rush i will let it run for a minute or so to cool the water in the radiator then start the engine again to circulate the cooler water through, but if i am in a rush i just let it cool on it's own. I figure that it isn't going to get any hotter while sitting still and i wasn't worried before i shut the bike off, so why worry after...





Nelly,
he means when you shut the engine off using the kill switch while leaving the key on.









Also a side note, if you do decide to let the fan run then i would suggest turning the key off and then back on so the headlights aren't on as well...

 

[Nelly]

I have noticed the same thing and sometimes if i am not in a rush i will let it run for a minute or so to cool the water in the radiator then start the engine again to circulate the cooler water through, but if i am in a rush i just let it cool on it's own. I figure that it isn't going to get any hotter while sitting still and i wasn't worried before i shut the bike off, so why worry after...





Nelly,
he means when you shut the engine off using the kill switch while leaving the key on.









Also a side note, if you do decide to let the fan run then i would suggest turning the key off and then back on so the headlights aren't on as well...

Cheers mate,
you have educated me. Now here is a first (drum roll.......ta la, I will educate you lol. The UK and European bikes have constant lights on when the ignition is on. It amazes me how the same bike can also be very different for our two countries.


Nelly

 

[reiobard]

Cheers mate,
you have educated me. Now here is a first (drum roll.......ta la, I will educate you lol. The UK and European bikes have constant lights on when the ignition is on. It amazes me how the same bike can also be very different for our two countries.


Nelly

You have also educated me then as well, the US bikes lights stay off until you start the engine. the side markers come on but not the headlights.

 

[GConn]

Nelly, I live in Cyprus (UK spec bike) and when my bike is switched on only the pod lights are lit. I need to start the engine for the headers to work.

But as reiobard said, if you turn the engine off using the side stand or kill switch the lights remain off untill you switch the key to off position.

 

[Nelly]

Nelly, I live in Cyprus (UK spec bike) and when my bike is switched on only the pod lights are lit. I need to start the engine for the headers to work.

But as reiobard said, if you turn the engine off using the side stand or kill switch the lights remain off untill you switch the key to off position.

Well I am lost then as mine stay on. I will just run out and check, but every evening I turn my engine off to push my bike in the garage the lights are off.
Give me two seconds.

Nelly

 

[brad81987]

I think the water temp sensor is located in such a way that if you just kill the bike the temp at the sensor sky rockets for some reason. I've had mine come on like that too but if I let it sit for a minute and then start it back up, the temperature drops like 20 or 30 degrees F.

 

[Nelly]

Well I am lost then as mine stay on. I will just run out and check, but every evening I turn my engine off to push my bike in the garage the lights are off.
Give me two seconds.

Nelly

Yep my lights are on with the ignition on

Nelly

 

[HavBlue]

You might as well shut her completely down because all the fan is doing is cooling the radiator and draining your battery, ain't no water circulating if the engine isn't running.

OK, this is only true to a certain extent. The transverse mounted engine of the FZ6 is made from aluminum and as we all know aluminum has shown to dissipate heat rather quickly. While it is true the fan does suck air through the radiator thus cooling the anti-freeze, it also blows cooler air full face to that block which in turn accelerates the cooling process rather rapidly. Yes, it does draw voltage but not enough to do any harm to a battery that is fully charged and in leaving it on I have yet to have mine stay on more than a minute or two.

Has anyone every noticed that front wheel drive cages have no cooling fan or fans that actually operate while the cage is running down the street? Yet that same engine on a conventional drivetrain has a cooling fan that operates right from the time it's started. The difference falls back on air flow to a longitudinal block because it is that efficient. Forcing air on to the side of that block will cool that block well and that little FZ6 fan will do wonders in a very short time.

 

[wolfc70]

I would not worry about it. The only time I let vehicles "cool down" is if they have turbos, I let them idle for a few minutes to keep the oil and water circulating. The FZ seems to cool down rather fast after you shut it off. I just let mine idle for 10 seconds or so after a brisk ride and shut it off.

 

[CanadianFZ6]

The answer is C.... just turn it off..... don't worry about it...:thumbup:

 

[wolfc70]

OK, this is only true to a certain extent. The transverse mounted engine of the FZ6 is made from aluminum and as we all know aluminum has shown to dissipate heat rather quickly. While it is true the fan does suck air through the radiator thus cooling the anti-freeze, it also blows cooler air full face to that block which in turn accelerates the cooling process rather rapidly. Yes, it does draw voltage but not enough to do any harm to a battery that is fully charged and in leaving it on I have yet to have mine stay on more than a minute or two.

Has anyone every noticed that front wheel drive cages have no cooling fan or fans that actually operate while the cage is running down the street? Yet that same engine on a conventional drivetrain has a cooling fan that operates right from the time it's started. The difference falls back on air flow to a longitudinal block because it is that efficient. Forcing air on to the side of that block will cool that block well and that little FZ6 fan will do wonders in a very short time.

This is true, but the main reason for tranverse engines having an electric fan is simply the fact that there is no easy way to have an engine driven fan with the radiator in front. The Morris minor was the only vehicle I ever have seen with a tranverse engine layout and a engine driven fan, the radiator was located on the inside fender.

That is one advantage of having a naked bike too, the heat can easily escape and rise away from the engine, no enclosed hood/fairing to contain the heat.

 

[grommit]

The Morris minor was the only vehicle I ever have seen with a tranverse engine layout and a engine driven fan, the radiator was located on the inside fender.

The Minor had a longitudinal engine layout and was rear wheel drive.

The Austin 1300 and Mini and many other cars that followed had a traverse mounted engine driving the front wheels. Probably what you were referring to.

The A-series ohv engine which powered these vehicles was tough little motor, the gearbox under the mini et al was more delicate.

I digress.

 

[HavBlue]

This is true, but the main reason for tranverse engines having an electric fan is simply the fact that there is no easy way to have an engine driven fan with the radiator in front. The Morris minor was the only vehicle I ever have seen with a tranverse engine layout and a engine driven fan, the radiator was located on the inside fender.

That is one advantage of having a naked bike too, the heat can easily escape and rise away from the engine, no enclosed hood/fairing to contain the heat.

Try running a conventional drivetrain vehicle without a radiator fan either mechanical or electric and let us know how long it will go without overheating.
Trust me, it will not be long. The cooling efficiency of the longitudinal drivetrain is a huge advantage. Not only is there no easy way to use the engine mounted mechanical fan, there's no need for it and in many cases the fan will hardly ever energize unless the AC is turned on........

 

[Tailgate]

This is interesting. We probably have all at one time or another heard an electric car radiator fan humming while car is parked. I am thinking whether the water circulates or not, cooling the fluid in the radiator helps cool the engine fluid as well since fluid transfers heat/cold even though it might not be circulating. Why doesn't the FZ6 fan run when the key if off? Interesting because some (most?) cars' radiator fans run after the ignition key is off (assuming the engine is still hot). Since Yamaha designed the fan to turn off with the ignition key, I'm okay with it? (I think I am)

 

[Fred]

Try running a conventional drivetrain vehicle without a radiator fan either mechanical or electric and let us know how long it will go without overheating.
Trust me, it will not be long.

I've done it on my 95 Nissan pickup with the 3.0 V6.

I was thinking about doing an electric fan conversion so I wouldn't have to hear the fan all the time. So I took off the fan and fan clutch and went for a drive.

At anything above 10mph, there was enough natural air flow through the radiator to cool the engine. The only time I came close to overheating was after idling for 10+ minutes at a rest stop to see how long it would take. The gauge got halfway between normal and overheat before I got bored and drove off. And I was trying to make it overheat.

There's two good reasons for RWD vehicles having engine driven fans.
1. It's a lot simpler and more reliable than electrics.
2. When towing, the extra capacity of the engine driven fan is more necessary.

Fred

Edit: I wound up leaving the fan off for a week in Texas summer. No problems so long as I avoided stop and go traffic.

 

[Fred]

Why doesn't the FZ6 fan run when the key if off? Interesting because some (most?) cars' radiator fans run after the ignition key is off (assuming the engine is still hot). Since Yamaha designed the fan to turn off with the ignition key, I'm okay with it? (I think I am)

Water is going to circulate even with the engine off. Colder water in the radiator will sink, and hot water from the engine will rise. So you'll get a slow circulation as the fan runs.

The FZ6's fan doesn't run with the key off because the FZ6 has a small battery. Car batteries have enough capacity to spin a fan for ten minutes and still be able to start the car later.

Fred