Radiator fan not turning on when hot

Tiny
RENHARD
  • MEMBER
  • 1998 SUZUKI MAROTI
  • 0.8L
  • 3 CYL
  • FWD
  • MANUAL
  • 45,000 MILES
So my radiator fan does not turn on when the vehicle is hot. I have tried bypassing the radiator fan switch and that starts the fan. So in fact the fan works when I bypass the switch, my first thoughts were maybe the switch is faulty. I have removed the switch tested it and there is continuity when it warms up in hot water. I even bought a new switch just encase and it is still the same problem of: 1). Radiator fan does not work even when the cars temperature is almost boiling 2). Yet still if I bypass the switch it works. So what could be happening for the switch to not be detecting that the vehicle is hot and turn on?

The only way I can drive the vehicle is by bypassing the switch, when I do so, the vehicle temperature remains normal but I do not want to continually have my vehicle like that, as I am afraid long distance travelling will burn out the electric motor if it is continually running.

Note: there is no fan clutch in my vehicle, there is no motor relay. It is is a small old Suzuki 1998.
Monday, July 24th, 2017 AT 12:07 PM

6 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
That would probably mean the radiator is clogged up and that sensor is never seeing the hottest coolant.
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Monday, July 24th, 2017 AT 2:39 PM
Tiny
RENHARD
  • MEMBER
  • 4 POSTS
Wrenchtech thank you so much. So I literally just thought about that and decided to pull down the radiator again, this time, I cleaned the radiator with water and run water through it through it hopping it will clear anything that clogged it up. Will retry radiator tomorrow. Do you think that is sufficient.

Also how does the fluid usually run through the radiator, is it from thermostat, to radiator then cool by fan then to the thermo fan switch then out the radiator, or is it the other way around.

Lastly after I fit up back the radiator how do I bleed out the air? The vehicle doesnt come with a bleeder. What I did previously was let the vehicle warm up with radiator cap off and anytime, topping up if the coolant level drops. Is that also sufficient?
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Monday, July 24th, 2017 AT 5:16 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
If the radiator really is blocked up, that likely will not help. It will be crusted up pretty solid.
We do not have that vehicle here in the US so I cannot give you any details about the system.
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Monday, July 24th, 2017 AT 5:24 PM
Tiny
RENHARD
  • MEMBER
  • 4 POSTS
So the fact that the water is now flowing through it properly does not prove that it is unblocked?
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Monday, July 24th, 2017 AT 5:40 PM
Tiny
RENHARD
  • MEMBER
  • 4 POSTS
Update fan is now working thanks for your help. Last night I soaked it in some vinegar, and this morning I wash it out again. I fitted up back everything, and it seem like air was in the system so I tried to bleed it out by removing the radiator cap. It still did not turn on, so after a while, I decided to rev the car up with radiator cap off and I realize the coolant level went down so I assume there was air still left in engine block. So I rev and top up, rev and top up until I could not top up any more. Then I covered the radiator cap but left the reservoir cap off. Then I took a short drive down the road at high rpm's, maxing my first and second gear. By the end of the road I heard the fan came in. Open the bonnet there and then and in fact the fan was running. I high rev up the road back. I reach back, and carefully remove the radiator cap (keep in mind the radiator cap was not that hot, because I only put it on to go down the road and back, less than two minutes total). I remove the radiator cap in hopes that if more air is in the system I would let it release. Rev up the car while it is in neutral, the level was basically constant. So I shut off the engine, re-cover the radiator, re-cover the reservoir as well, gave it five minutes rest time. Then start the engine one last time, not revving, just a normal start and waited to see if the fan would chip in which it did. So far so good. Thanks again Wrenchtech for all the help.
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Tuesday, July 25th, 2017 AT 9:34 AM
Tiny
WRENCHTECH
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You are welcome.
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Tuesday, July 25th, 2017 AT 12:42 PM

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