Thermal switch- fans not cutting in

Message

control_67 · #1 Post by **control_67** » Sat Aug 18, 2012 5:54 pm

This morning I went back hoe to visit the family, it's a 45 minute ride on a good day asking in the m23 and 25. As usual there was heavy traffic on the m25 and I cut off early for a little break as I was boiling in my leathers. When I stopped the bike was strangely quiet- no fan running. The temp was showing as 98 degrees so I let the bike stand for a while before setting off again on quiet roads. The temperature dropped abit but stayed in the low 80s.

It needs a new switch I think, the fans work with the switch bypassed and on the ride home the temp didn't get above 75 with them running full time, this was motorway miles though so speed didn't really drop below 70 and there wasn't any traffic to get stuck in this time.

Is it likely that it was the switch? Or is it possible that it wasn't actuating due to the coolant not getting round the system o an airlock?

flatlander · #2 Post by **flatlander** » Sat Aug 18, 2012 6:33 pm

Mine recently went only really confirmed by changing coolant which was due anyway. Changed and checked now cuts in at 87yhough the day of my latest roundabout drama it did get way above 100 and pissed itself but has worked fine since

Not sure that helps but if the coolant looks ok sounds like the switch

fatboy · #3 Post by **fatboy** » Sat Aug 18, 2012 7:10 pm

This is the procedure I would use on a car so dont see why it wont work on a bike
Disconnect the wiring plug from the thermo switch and bridge the wiring contacts with a short piece of wire,turn on the ignition, if the fans come on the switch is at fault.
If its a 3 pin connector you may not bridge the right ones so try again.
You wont hurt your running a bit cool in summer
Cooling fans usually cut in at 95 to 98, cut out 90 ish

anzacinexile · #4 Post by **anzacinexile** » Sun Aug 19, 2012 10:06 am

Mine got "sticky" due to lack of use. Cured it by removing the switch and with a saucepan of cold water and boiling water alternately dunking the thing between the two pans. After exercising the switch a few times (you can feel the click), reassembled and all was well

D-Rider · #5 Post by **D-Rider** » Sun Aug 19, 2012 5:55 pm

anzacinexile wrote:Mine got "sticky" due to lack of use. Cured it by removing the switch and with a saucepan of cold water and boiling water alternately dunking the thing between the two pans. After exercising the switch a few times (you can feel the click), reassembled and all was well

Ah the "Jolly Jumbuck" method.

Take 2 billys, fill both with water.
Light fire and place one billy over fire.
Don't rush things, wait until your billy boil.
Dunk alternately in hot and cold billys.
Hey presto, and it's waltzing Matilda all the way.

control_67 · #6 Post by **control_67** » Sun Aug 19, 2012 6:49 pm

For what it's worth I'll probably change the switch, it's going to be less hassle in the long term, hopefully. I know with some bikes you can find car switches that fit and are considerably cheaper, any such luck for the falco that anyone knows of?

I'll probably drain (and refill) the coolant next weekend, seeing as I have no idea when it was last done, I will probably need to adjust the chain then anyway so it makes sense to do other jobs at the same time. What ratio of water to antifreeze should I use, or is there any reccomended product for coolant?

Cheers all.

fatboy · #7 Post by **fatboy** » Sun Aug 19, 2012 7:53 pm

Good luck with the rad switch, take the old one out and do a trawl of the shops, physical size is the main difference between switches, they all share very similar operating perameters.
As for the coolant,mininimun 25% coolant will see you ok in the worst UK winter or summer, 40 or 50% is bombproof, alot of transport companies run on 100% coolant.
IMHO 30/ 40 %

Aladinsaneuk · #8 Post by **Aladinsaneuk** » Sun Aug 19, 2012 8:10 pm

i used http://www.halfords.com/webapp/wcs/stor ... yId_255224

iirc you need 3 litres in total

be warned, its quite a straight forward job... BUT you will be topping the tank up for a couple of days!

anzacinexile · #9 Post by **anzacinexile** » Sun Aug 19, 2012 8:13 pm

D-Rider wrote:
anzacinexile wrote:Mine got "sticky" due to lack of use. Cured it by removing the switch and with a saucepan of cold water and boiling water alternately dunking the thing between the two pans. After exercising the switch a few times (you can feel the click), reassembled and all was well
Ah the "Jolly Jumbuck" method.
Take 2 billys, fill both with water.
Light fire and place one billy over fire.
Don't rush things, wait until your billy boil.
Dunk alternately in hot and cold billys.
Hey presto, and it's waltzing Matilda all the way.

Yeah, very good cobber, fair dingcum strine you got there for a pom.........(etc, etc)

Sleepyboy · #10 Post by **Sleepyboy** » Sun Aug 19, 2012 8:46 pm

fatboy wrote:Good luck with the rad switch, take the old one out and do a trawl of the shops, physical size is the main difference between switches, they all share very similar operating perameters.
As for the coolant,mininimun 25% coolant will see you ok in the worst UK winter or summer, 40 or 50% is bombproof, alot of transport companies run on 100% coolant.
IMHO 30/ 40 %

I always understood that using 100% antifreeze actually lowered the boiling point of the coolant losing cooling capacity???

struv · #11 Post by **struv** » Sun Aug 19, 2012 8:55 pm

coolant and antifreeze are two different things coolent usualy is available ready to use in a 50/50 mix buy the red as it has a longer lifespan. and yes deffo do not use 100% pure antifreeze

Aladinsaneuk · #12 Post by **Aladinsaneuk** » Sun Aug 19, 2012 9:12 pm

tbh - the pre mixed stuff is a damn sight easier - its there, its already mixed and you just put it in.... start pissing around with measuring jugs etc - I do that for my home brew - not for anti freeze :)

b_chiller · #13 Post by **b_chiller** » Mon Aug 20, 2012 1:34 pm

I had the same problem earlier in the year. I set out to change the thermo switch etc etc and all it ended up being was a build up of green crud on one of the pins on the cooling fan relay in the fuse box near the front left handle bar.

As you can see from my message Im not very technical so I was like a pig in poop when thats all it ended up being!

Tonyunn · #14 Post by **Tonyunn** » Mon Aug 20, 2012 2:55 pm

Thanks to the forum (control 67) I checked mine today, sat there engine running fans kicked in at 95c job done cheers.

fatboy · #15 Post by **fatboy** » Mon Aug 20, 2012 7:07 pm

I have no idea why people use 100% cooolant, must be some benefit as it is (or was ) company policy by Firstbus.
Yes there was a difference between coolant and anti freeze, most is now combined and labelled as such,if you were to buy summer coolant or winter anti freeze you may notice the price is tuppence hapenny for each.
Red coolant does not last longer than other coloured coolants, it simply changes colour as its properties degrade making it easy to do a visual check.
I would replace coolant once a year on a bike because of the small rad size,car, van , lorry, every other year adding 10% more collant in winter