Author Topic: Possible Thermo Switch Issue  (Read 2457 times)

Offline alans1100

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Possible Thermo Switch Issue
« on: September 03, 2016, 04:50:00 PM »
When returning from Port Pirie yesterday Heather wanted me to stop so she could get some rabbit food and rather than stop the motor I let it idle for the 10 minute wait.

I noticed the temp gauge in the red where normally the fan would keep it at just over half of the normal range. Once underway the temp slowly went down to normal which proved that at least the water pump was still working and there was still some coolant left.

We went to Adelaide in May and with the stop/start traffic I had no issues with temp and until yesterday haven't idled the motor when it's hot for more than a minute or two so not long enough to notice any issues.

Three possible fixes; fuse, thermo switch or fan. Haven't looked at the bike yet and I have a ride to Port Augusta on Monday morning and then I'm off to Perth on Thursday so I'll have to check it out when I get back.
1999 :bl11  2004 :13Candy

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Offline STroppy

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Re: Possible Thermo Switch Issue
« Reply #1 on: September 04, 2016, 08:22:53 AM »
I'm guessing it wasn't an overly hot day . . I found the temp guage on my 1100 tended to rise into/close to the red when in stop/go traffic when ambient temp was high, I replaced the temp sensor/fan swith and put in a new thermostat, cost wasn't exorbitant and seemed to fix the problem and, from memory, not a difficult job.
Terry, Canberra 0412499625
Ulysses #22354, FarRider #761
Current bikes 2013 Triumph Trophy SE, 2008 ST1300
Previous bikes1948 Triumph Tiger 500 Twin - sprung rear hub, 1963 BSA Bantam 175, Yamaha 75cc & DT250, Honda ST1100, 400N & CX500 sports, BMW K100RS & K100 LT, Harley Electra-glid
 

Offline alans1100

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Re: Possible Thermo Switch Issue
« Reply #2 on: September 04, 2016, 06:35:36 PM »
Not that warm, more cool than anything - about 5:30 pm.

For peace of mind I checked the coolant this afternoon; couldn't see anything in the reserve tank so went further and removed the plastic for access to the radiator cap. All good there so just topped the reserve tank to the high level. Any excess will come out on tomorrows ride.

Checked the fan fuse which was ok so that leaves the fan and thermo switch with the latter the likely culprit. Can't complain after all she is 17 years old and fairing better than I am or so it seems.

While the plastic was off I swapped out the air cleaner which I've had laying around since I repaired the fuel sensor back in March. The last one went in way back in early 2011 (or was it 2012?) or whenever I had 120,000 km on the clock.

Wondering if one of these would do the trick though while in Port Augusta tomorrow I'm getting a price off the dealer

http://www.ebay.com.au/itm/Replacement-Radiator-Fan-Thermo-Switch-Honda-SWITCH-ASSY-THERMO-37760-MT2-003-/171631570811?hash=item27f609ef7b:g:3AUAAOSw~uhUq8jS
1999 :bl11  2004 :13Candy

FarRider #921- BR15, BR17, CR1

 

Offline Yorkie

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Re: Possible Thermo Switch Issue
« Reply #3 on: September 05, 2016, 08:48:24 PM »
with ignition on earth the switch lead and the fan should run, if so then switch is the problem, if not look to power supply to fan or fan itself
Brian 0418937173
Manager York Motor Museum

In the shed
1999 ST1100A
1971 CB750K2
1980 XV750
1977 GL1000
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So at what age does this "old enough to know better" kick in?
I believe in the "hereafter", every time I go to the shed I have to think "what am I here after"
 
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Offline alans1100

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Re: Possible Thermo Switch Issue
« Reply #4 on: September 05, 2016, 11:03:29 PM »
Testing the switch etc. will have to wait until after I get back from Perth.

Priced the fan switch for $82 plus some O rings for the next tyre change as well.
1999 :bl11  2004 :13Candy

FarRider #921- BR15, BR17, CR1

 

Offline alans1100

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Re: Possible Thermo Switch Issue
« Reply #5 on: January 07, 2017, 05:54:00 PM »
The saga continues -

Though I haven't yet sorted the thermo switch and being aware of it we have avoided going to the city where I no doubt need the fan working.

On our last trip to Port Pirie we were held up by road works. No drama with overheating in the morning as the temp indicator didn't seem to go any higher than the "P" in temp or about where the fan usually cuts in before we started moving again.

The same hold up again in the afternoon but we sat idling for a little longer and then it sounded like the fan cut in and the temp gauge had the same indication as the morning. I've had the bike so long I can just about tell when the fan cuts in but I still wasn't 100% certain knowing the recent history.

Today after a ride down the shop I let the bike idle until either the fan came on or gauge went soaring to the end of the gauge. Maybe about 5 mins later the fan sounded as if it came on. I could feel air flow from the front side of the motor and I could here the sound of the fan and then it stopped.

Anyway switch is still on the to do list.

1999 :bl11  2004 :13Candy

FarRider #921- BR15, BR17, CR1

 

Offline pabrizzer

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Re: Possible Thermo Switch Issue
« Reply #6 on: February 25, 2017, 08:41:27 AM »
I'm having some cooling issues with my 1100 at the moment.
Hope its not a crack in head or gasket.
I do reckon when the coolant gets low the thermo switch stops working.
Hoping to find how to put a bypass switch for the fan on this site somewhere....