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Author [ES] [CA] [PL] [PT] [IT] [DE] [FR] [NL] [DK] [NO] [GR] [TR] Topic: Radiator fan turns on quite often?  (Read 368 times)

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Offline tavurth

  • Inazuma Junior
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  • Bike: GW250
  • City / Town: Bodrum
  • Country: Turkey
Radiator fan turns on quite often?
« on: May 22, 2022, 09:40:44 PM »
On a longer tour at the moment in the East of Turkey, ambient temperatures usually around 25°c.

After the first 1,000 km or so I noticed that the radiator fan had started to turn on while riding. Perhaps it had always been turning on after a while riding but I didn't notice it before, even in up to 35°c.

At some point on a highway, the heat warning light came on. I immediately stopped in the closest town and changed the coolant at a local Honda/Suzuki service center. They did a full radiator flush as the last change was around 8k km before. Radiator looked full when opening.

They seemed happy with the result after testing and sent me on my way. However the fan is still turning on while I ride longer distances or ride some more technical roads slowly.

The sweet spot seems to be when I'm below 6k rpm and maintaining a good speed (70kph or so)

When feeling the radiator it is hot to the touch so I guess my coolant pump is working fine. The heat warning light has not turned on since the coolant change.

Does your radiator fan turn on after only a short while?

If not, any ideas about what to check next?
« Last Edit: May 22, 2022, 09:48:19 PM by tavurth »

Offline tavurth

  • Inazuma Junior
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  • Country: Turkey
Re: Radiator fan turns on quite often?
« Reply #1 on: May 22, 2022, 11:15:55 PM »
So I dug through the Suzuki online manual for a bit and think I found some answers:

See Figure A for a nice overview of temperatures.

The heat warning light will turn on at 120°c (Fig. A)
The cooling fan will turn on at 105°c (Fig. A)

With the Suzuki recommended coolant, boiling temperature should be at around 123°c (Fig. B), so just after the warning light turns on.

The manual also has a few ideas why it might be running hotter than 105°c (Fig. C):

- I'm pulling quite a bit of weight due to luggage
- Radiator might have some gunk inside
- Thermostat could be faulty

If others are also seeing the fan turn on due to normal operation then I guess the Zuma just runs around 105°c anyway.
« Last Edit: May 22, 2022, 11:24:37 PM by tavurth »

Offline tavurth

  • Inazuma Junior
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  • Bike: GW250
  • City / Town: Bodrum
  • Country: Turkey
Re: Radiator fan turns on quite often?
« Reply #2 on: May 22, 2022, 11:21:36 PM »
So I also found these two data points from a factory Inazuma.

The first is at idle throttle (1500rpm), we can see the temperature slowly climb to what looks like 88.3°c but I can't see so well because their screenshot is blurry.

The second is at low throttle (3000rpm), and the temperature is remaining constant at 104.3°c.

So it seems likely that the fan is turning on for everyone but I just never noticed it before 😅

Offline tavurth

  • Inazuma Junior
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  • Posts: 10
  • Bike: GW250
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  • Country: Turkey
Re: Radiator fan turns on quite often?
« Reply #3 on: June 06, 2022, 02:28:51 PM »
Previously the warning light was not turning on, but the fan would start even under a moderate load, which seemed weird.

Due to this, after completing the main leg of my tour I stopped and dumped the oil.

Since replacing the oil (~3500 early replacement) the fan has not turned on at all, and in general the motor seems much happier and more performant.

Perhaps there was some bad or aged oil in the last batch I used, thankfully everything now back to normal  :152:

Offline Resident Weevil

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Re: Radiator fan turns on quite often?
« Reply #4 on: June 06, 2022, 10:58:42 PM »
Thanks for the info!  :028: