jarst

Main Fan and Sub Fan Operation

17 posts in this topic

Hi all,

I just got my hands on a 2009 2.0X. Funnily it does not come with a coolant temp gauge, so I got one of those bluetooth OBD2 adapters. 

Found out that my coolant temp hovers around 98 to 102degC during idling/city driving.

During standstill idling, I found out that when:

- AC ON, Main fan comes on, Sub fan comes on/off at 97degC

- AC OFF, BOTH fans OFF, even when coolant temp reaches 100degC

Hope could get some advise if this is normal? And what are your usual coolant temps?

Thanks a lot!

J

 

 

Edited by jarst

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HI, you are better off getting answers from the SFSG (Subaru Foresters Singapore) Fb group. PM me your email address and name and i will invite you from the page. 

 

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Hi, I'm Justus, sohjustus@gmail.com

Thanks a lot 

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@davidtht Hi David, while we are glad that you are taking time to help the members, please note that we do not condone 'spamming' the SFSG facebook group here in SCS. Forums are here for a reason which is for members to share information, ask questions, and get help from other members. Online forums allow information to be stored in a systematic and organized way which can be search by all and indexed by Google.

Facebook on the other way, does not work that way.

We appreciate if you could share your wisdom and knowledge here so other members may also benefit.

Thank you.

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On 06/08/2016 at 9:42 PM, jarst said:

Hi all,

I just got my hands on a 2009 2.0X. Funnily it does not come with a coolant temp gauge, so I got one of those bluetooth OBD2 adapters. 

Found out that my coolant temp hovers around 98 to 102degC during idling/city driving.

During standstill idling, I found out that when:

- AC ON, Main fan comes on, Sub fan comes on/off at 97degC

- AC OFF, BOTH fans OFF, even when coolant temp reaches 100degC

Hope could get some advise if this is normal? And what are your usual coolant temps?

Thanks a lot!

J

 

 

When does the Fan come on with the AC off ? Does the temp go above 100degC ?

 

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The fans do not come on with when the AC is off. Water temp reaches 101-102degC max. 

I heard from a friend who owned a Forester saying the fan only comes on at 109degC. Is that true?

Normal cruising along highway water temp ranges from 98degC to 102degC depending on outside temp.

Driving faster seems to cool down the water temp a bit.

Received your FB invite, thanks!

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My understanding of how the radiator fan and air con fan works is:

1) Radiator fan will activate based on thermostat temp
2) Air con fan will activate based on AC on

I read somewhere before that OEM Subaru thermostat fully open always below 100 degrees.

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Same thing happened to my old Exiga. Temp went up as high as 105deg C. First, the radiator broke/cracked. Then the hose came off unexplicably. Seems that the thermostat was not doing its job. The water pump was also kicking in at a higher temp. Did a full timing belt change and niw the temp has not gone past 93. 

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11 minutes ago, LCH said:

My understanding of how the radiator fan and air con fan works is:

1) Radiator fan will activate based on thermostat temp
2) Air con fan will activate based on AC on

I read somewhere before that OEM Subaru thermostat fully open always below 100 degrees.

 

6 minutes ago, redviper51 said:

Same thing happened to my old Exiga. Temp went up as high as 105deg C. First, the radiator broke/cracked. Then the hose came off unexplicably. Seems that the thermostat was not doing its job. The water pump was also kicking in at a higher temp. Did a full timing belt change and niw the temp has not gone past 93. 

So it's likely that thermostat is not working properly and not activating the radiator fan and water pump?

Edited by jarst

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since you bought the car, have you flush the radiator ? when was the last time water pump was changed ? 

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14 minutes ago, davidtht said:

since you bought the car, have you flush the radiator ? when was the last time water pump was changed ? 

Yup, a few times when I changed the whole coolant. 

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one option is to check the thermostat   to see if it;s block or choked and switch to low temp  thermostat . 

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12 minutes ago, davidtht said:

since you bought the car, have you flush the radiator ? when was the last time water pump was changed ? 

Have not flushed radiator yet. And no idea when water pump was changed. 

I guess I will open the radiator cap to check for coolant flow, then change coolant. 

If temp still high then replace thermostat. 

But is 100degC still safe?

 

 

 

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usually water pump is changed same time as timing belt and thermostat  replace is when you flush radiator. So if you plan to flush the radiator, i suggest changing the thermostat.

 

personally, i find 100degC a bit high for daily driving. 

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Thanks for all the advice guys, appreciate it!

Got an update, the OBD bluetooth adapter I connected was screwing around with the electricals and sensors. The water temp, AT temp, engine check, ABS, ESP all lit up. 

It even messed with the gearbox, could not downshift and power steering felt funny.

Stopped at the side, turned engine off and on, all lights cleared left engine check and ESP. Car drove normally.

Took this chance to get some professional advice from B/\/\S. They reset the faults and it was clear. 

Told them about the water temp issue, and their mech said it is quite normal. Especially for cars without the water temp gauge in the instrument cluster, the water temp, tends to be higher. As long as temp goes down when it hits 102-103degC and does not shoot up above 110degC it is fine.

He also said low temp thermostat won't help much, might as well remove the whole thermostat, coolant will be constantly flowing.

And saw the rad fan in operation when the AC was off, I think it is speed activated. It will not activate when car just turned on in idle, but will activate when car in motion and stops.

So yea, thanks again guys.

Cheers!

 

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