Fan motor assembly or thermal sensor problem

**rcdgreat** · February 14th, 2018 04:39 AM

Hi Mga ka tsikot... ask lng po ako regarding sa sasakyan ko. Muntik po ako mgoverheat dahil nabutas po ung lower hose ko sa radiator napalitan na po sya ng bago pero ang concern ko po ngaun eh pag inistart ko po ung sasakyan ko ng walang naka off ung aircon tuloy tuloy ang akyat ng temp. hindi na sya nababa pero kapag from cold start pinaandar ko ung sasakyan ng naka aircon ok naman ung temp. sa fan motor assembly na po kaya ang sira nun? bagong palit lang din po ang thermostat ko. tapos pansin ko rin po pag inistart sya ng walang aircon tska lang nag oon ung fan pag umabot na ng 100celsius ung temp may bluetooth obd po kasi ako kaya namomonitor ko po ung temp.

tska po kung sakali man na fan motor assembly na ang problem ok lang po ba na replacement na lang ang ipalit sobra po kasi mahal ng orig parts. Mazda 3 2004 model po sasakyan ko. Salamat po ng marami!!!

**kisshmet** · February 14th, 2018 02:12 PM

100 deg celcius is the boiling point of water, the engine will overheat if the temperature is allowed to rise beyond that. the aux fan is activated to cool the radiator and to keep it from melting.

Additionally, the aux fan has a secondary function which is to cool down the condenser of your vehicles aircon system. When the aircon is on, the conderser will function to absorb the heat generated by the aircon compressor. The aircon system isnt allowed to get too hot hence the aux fan is also activated to further cool down the condenser. Otherwise the metal tubing of your vehicles condenser will melt

Theres nothing wrong with your cars cooling system. since both the radiator and aircon condenser is located in front of the aux fan, when the aux fan is activated due to rising temp of the condenser your radiator is cooled down also

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**oj88** · February 14th, 2018 02:49 PM

A pressurized cooling system can go as high as 115°C without boiling. In one of my previous vehicles, I was constantly hitting 105 to 108°C while stuck bumper-to-bumper in hot weather.

The TS' issue is likely the fan motor not working unless the A/C is turned on. Definitely an electrical problem... I'd start with the ECT or fan thermostat, whichever is equipped on his car. Also the relays, any fuses.

**rcdgreat** · February 15th, 2018 12:29 AM

Originally Posted by oj88

A pressurized cooling system can go as high as 115°C without boiling. In one of my previous vehicles, I was constantly hitting 105 to 108°C while stuck bumper-to-bumper in hot weather.

The TS' issue is likely the fan motor not working unless the A/C is turned on. Definitely an electrical problem... I'd start with the ECT or fan thermostat, whichever is equipped on his car. Also the relays, any fuses.

Hi Sir oj88,

First and foremost I would like to thank you for your inputs regarding my current issue. just want to clarify regarding the issue with my fan motor. It does turn on even without the A/C turned on but it is turned on when the temp reaches 100°C and even when turned on it doesn't have any effect on lowering the temp of my car it continues to rise up. Just want to ask also if the fan thermostat you've mentioned is that the one that triggers the fan to turn on in a specific temp range?

Additional question is if ever I would replace my fan motor assembly can I use an aftermarket / replacement for that? Coz I've checked the price of an OEM and its quite expensive.

Thank you very much for your help.