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Radiator fan not kicking in!

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Alexhoc

Registered User
I have changed the radiator on the bike, now the fan won't kick in when it gets hot. The temperature gauge works fine, it reads as I would expect it to when riding along. All the cables are plugged in correctly. How can I diagnose the problem?

Also, the radiator has a tiny leak, where the return pipe outlet is connected to the rad. What's he best way to fix that?
 
M

mikeyw64

Guest
Alexhoc said:
I have changed the radiator on the bike, now the fan won't kick in when it gets hot. The temperature gauge works fine, it reads as I would expect it to when riding along. All the cables are plugged in correctly. How can I diagnose the problem?

Also, the radiator has a tiny leak, where the return pipe outlet is connected to the rad. What's he best way to fix that?
Click to expand...

FI or Carby ?


If FI and you have one of the CHinese radiators then some people have found the fan is a snug fit and may not be turning and may even be blowing the fuse.

May be worth checking the fnis fre. If it is then disconnect it and put a + & - diretly to the fan so you cn rout any wiring issue
 
A

Alexhoc

Registered User
It is FI with a chinese radiator, so that could be a good shout, I'll go have a look.
 
A

Alexhoc

Registered User
Yep, correct on both counts!

The fan turns but scrapes somewhere, so I'll have to try and move the rad forward somehow, then fit a new fuse and take it from there.
 
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mikeyw64

Guest
Alexhoc said:
Yep, correct on both counts!

The fan turns but scrapes somewhere, so I'll have to try and move the rad forward somehow, then fit a new fuse and take it from there.
Click to expand...

Can't find the picture now but my mate (not on here) used a small bracket (think meccano strip) so push the bottom out a bit
 
Centaur

Centaur

Site Pedant
Club Sponsor
Not bad on here is it, Alex?

About an hour and your problem solved. Well, located anyway! @tu*
 
noobie

noobie

Clueless in most things
Is there enough room to use a washer or two, between where the rad an the fan mounts so giving the fan a bit more space to work?
 
A

Alexhoc

Registered User
Looks like the fan is in the right place against the rad, but the mounting points on the rad are a touch too far forward, thus pushing the fan against the engine a bit. There wasn't much clearance to start with so I didn't notice it at first, only when I tried to move the fan back and realised there was no room.
 
A

Alexhoc

Registered User
Right, that's fixed, the fan is now turning free and kicking in when the bike gets hot.

Thanks for the help, it's funny how it's the simplest things that you just completely overlook!
 
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mikeyw64

Guest
Alexhoc said:
Looks like the fan is in the right place against the rad, but the mounting points on the rad are a touch too far forward, thus pushing the fan against the engine a bit. There wasn't much clearance to start with so I didn't notice it at first, only when I tried to move the fan back and realised there was no room.
Click to expand...

Have you sorted it now though?
 
Dickiebird

Dickiebird

Registered User
When I saw the title of your post I thought great coincidence, because I came back from a ride on Friday and when I cut the ignition in the garage I heard a strange gurgling noise from below and there was coolant on the garage floor. Temperature was showing 127 deg ! I then realised the fan hadn't kicked in , so I let it cool down, disconnected the fan and connected it to directly to the battery and it worked ok. The bikes an FI so I have now sent for a new relay from DSS, and if that don't work I'll get a new coolant temp sensor (?50 approx !). If that don't work I'll be back ! Watch this space.
 
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mikeyw64

Guest
Dickiebird said:
When I saw the title of your post I thought great coincidence, because I came back from a ride on Friday and when I cut the ignition in the garage I heard a strange gurgling noise from below and there was coolant on the garage floor. Temperature was showing 127 deg ! I then realised the fan hadn't kicked in , so I let it cool down, disconnected the fan and connected it to directly to the battery and it worked ok. The bikes an FI so I have now sent for a new relay from DSS, and if that don't work I'll get a new coolant temp sensor (?50 approx !). If that don't work I'll be back ! Watch this space.
Click to expand...

Or just run a manual override switch to earth in
 
Dickiebird

Dickiebird

Registered User
mikeyw64 said:
Or just run a manual override switch to earth in
Click to expand...

Managed to check the relay today by swapping it with the headlight relay, which kicks in when you switch to main beam. It worked O.K. , so I have ordered a coolant temp sensor from DSS. If that don't work I may do what you suggest Mikey. I can't work out what else it could be. :dunno:
 
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mikeyw64

Guest
Dickiebird said:
Managed to check the relay today by swapping it with the headlight relay, which kicks in when you switch to main beam. It worked O.K. , so I have ordered a coolant temp sensor from DSS. If that don't work I may do what you suggest Mikey. I can't work out what else it could be. :dunno:
Click to expand...

I can't see it would be the sender given the tem guage is working correctly.


On the FI (if Ive got it right) the signal goes from the sender to the ECU which then sends it to the gauge or at a set value sends a signal to the relay.

You could try (after checking the wiring diagram) putting a ( direct to the input side of the relay.


If the fan kick in then the problem lies between the ECU & the Fan relay.


If it doesn't kick in then (given the relay works) its an earthing problem from the relay
 
Dickiebird

Dickiebird

Registered User
mikeyw64 said:
I can't see it would be the sender given the tem guage is working correctly.


On the FI (if Ive got it right) the signal goes from the sender to the ECU which then sends it to the gauge or at a set value sends a signal to the relay.

You could try (after checking the wiring diagram) putting a ( direct to the input side of the relay.


If the fan kick in then the problem lies between the ECU & the Fan relay.


If it doesn't kick in then (given the relay works) its an earthing problem from the relay
Click to expand...

I thought the same as you regarding the fact that the temp gauge is still working , but the Haynes manual says that to test the sensor you have to remove it , put it into a container with oil in it, heat it up, and then stick a meter on it. If the temp gauge not working was a sure sign that the sensor was kaput there would be no need for all that rigmarole.According to the wiring diagram, ( if I've read it correctly), the sensor sends one signal to the ECU and a separate signal directly to the gauge. But , then again , the haynes manual is not the most reliable book on the planet ! Anyway, I tried what you suggested, Mikey, and connected a live feed to the ECU terminal on the base of the relay, but nothing happened, so , are you now saying that if I connect the earth terminal directly to earth, that might do the trick ?
 
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Dickiebird

Dickiebird

Registered User
Yes ,I did. I think I wrote somewhere on here that I had read the wiring diagram and noticed that the feed for the fan came directly from the ignition switch. By coincidence a few weeks earlier I had replaced my switch because I had repaired (soldered )one of the wires which had broken , and I wasn't really happy with it. So, I bought one of the cheap(chinese)switches off the bay of fleas. My suspicions were immediately aroused! I then swapped the switches back as they were, and lo &behold the fan worked correctly. So,the moral of this story is, whatever you do, do not be tempted to cut costs the chinese way !!! :bang:
 
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