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Cooling fans not coming on

Posted: Sat Jun 14, 2014 3:06 pm
by cmdrew
Well finally got my engine in and running having had to replace a number of items such as the camchain tensioners and neutral switch.

It does seem to rattle quite a bit from the clutch which goes away if you pull the clutch in. I'm used to this on a Ducati but I'm not sure if the Aprillia normally has this clutch rattle as it is a wet clutch?

I'm also finding that the fans are not cutting in. They are both wired up as far as I can see but I have had the temperature readout up to 104 degrees and the fans did not cut in - I understood that they should cut in at 100. Checked the fuse and that's OK but I find it hard to believe that neither is working so would welcome any suggestions.

Posted: Sat Jun 14, 2014 3:49 pm
by zoidberg
if they're both not working and the fuse is ok, next to check is the relay and temp sensor. if you bridge the sensor wire they should come on. if so buy a new sensor.

Posted: Sat Jun 14, 2014 4:08 pm
by cmdrew
Is the temp sender different to that which sends the temperature to the dash? If so which sender do you mean and where is it?

Posted: Sat Jun 14, 2014 4:13 pm
by zoidberg
it'll be on the cooling system with two wires, the temo sender for the gauge usually has one wire.

i can't go check as i'm about 65 miles offshore

Posted: Sat Jun 14, 2014 6:24 pm
by fatboy
The coolant tempsensor ( I think ) lives in the manifold by the thermostat. Check you have voltage to the switch and terminals are free of crud.
There is also a fan relay whih may be the culprit, very small possibility the thermostat may not be opening, if this is the case you will be overheating very quickly and the rads will be cold to touch.
As Zoidberg said, when you brige the two terminals of the fan swich connector and fans kick in then the temp switch is shot.
This project hasn t been easy on you !

Posted: Sat Jun 14, 2014 6:31 pm
by zoidberg
also bridging the switch checks the relay, so check for a click in there. on the lhs relay box its the lowest relay in the panel.

Posted: Sat Jun 14, 2014 6:57 pm
by cmdrew
Really odd - I have found the wires for the fan switch and bridged them and the fan comes on so all good there. Unfortunate
Y the wires are not connected up (and weren't when I replaced the engine) and I can't find anywhere to plug them in to!

The manual suggests that the switch should be in the 3 way coolant manifold on the left hand side of the engine but mine just has a bolt there - no switch. Any where else the switch could be or has it just been removed at some point on my bike?

Posted: Sat Jun 14, 2014 7:18 pm
by zoidberg
it will look like a bolt, perhaps the terminals have snapped off? or it has been blanked?

Posted: Sat Jun 14, 2014 7:28 pm
by cmdrew
No definitely just a bolt. Looks like I need to get a new one then!

Posted: Sat Jun 14, 2014 7:35 pm
by zoidberg
yip seems so. glad you got is sorted. would have been messy if it had boiled itself!

Re: Cooling fans not coming on

Posted: Sun Jun 15, 2014 10:30 am
by Dalemac
cmdrew wrote:It does seem to rattle quite a bit from the clutch which goes away if you pull the clutch in. I'm used to this on a Ducati but I'm not sure if the Aprillia normally has this clutch rattle as it is a wet clutch?
Yes, this is entirely normal for a falco. Nothing to worry about.

Re: Cooling fans not coming on

Posted: Sun Jun 15, 2014 6:40 pm
by fatboy
Dalemac wrote:
cmdrew wrote:It does seem to rattle quite a bit from the clutch which goes away if you pull the clutch in. I'm used to this on a Ducati but I'm not sure if the Aprillia normally has this clutch rattle as it is a wet clutch?
Yes, this is entirely normal for a falco. Nothing to worry about.
I replaced the bearing and its just as noisey !

Posted: Fri Jun 10, 2016 6:23 pm
by mangocrazy
Reviving an old thread, as when I came to fire the red Falco up after some work, the temps went up to 101-102 deg C and the fans never came on. Normally they kick in at around 95 C.

So first step is to bridge the two contacts on the switch bolted to the 3-way manifold, I take it? This effectively tests out the relay, I presume. And, assuming the fans do come on when the contacts are bridged, if the fans don't come on after that when the engine is up to temperature then the switch itself is toast?

Posted: Sat Jun 11, 2016 12:46 pm
by ginge
Always the thermal switch, I've had two go on mine for some reason!

Part number here: AP8112939

Posted: Sat Jun 11, 2016 3:31 pm
by mangocrazy
Nice one, thanks for that. I have a suspicion that one or both of the spade terminals may have been disturbed, as Griff's chaps fitted one of their air kits recently, but can't check as the bike is 70 miles away. That's the hope, anyway. Replacing the thermal switch will be a nuisance I could do without.

Thanks for the part number - appreciated.