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2011 Outback Limited 2.5i/2018 Crosstrek limited
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Discussion Starter #1
New game show folks...I just had the timing belt and all related parts changed out this past Friday. Along with that the thermostatwas replaced too. My temperature had been fluctuating and the air temps were a little wonky...lower temps than what was reading when set on Hvac. Today on trip to...from work the temp still fluctuates but at lower temps now...between 190.4C and 195 C. No leaky head gaskets. Reading another thread where one posters problem was the water pump...normally I would chaulk this up to bad thermostat or head gasket but this one has me guessing. Wondering if it could be the water pump...which I decided not to do with the timing belt

Any ideas...anyone...anyone...
 

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2012 OB , 2017 Impreza
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Sounds to me there is still air in cooling-system.


Keep the overflow reservoir full and let the system go through several HEAT/COOL cycles. (DO NOT OPEN RADIATOR!!)


After several HEAT/COOL cycles, the system should self-burp all the air out and suck in coolant from the reservoir.
 

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Discussion Starter #3
Sounds to me there is still air in cooling-system.


Keep the overflow reservoir full and let the system go through several HEAT/COOL cycles. (DO NOT OPEN RADIATOR!!)


After several HEAT/COOL cycles, the system should self-burp all the air out and suck in coolant from the reservoir.
...lol...I drove home today with the heat on bust and the sunroof openwhile just playing around with it...still had the same issue...will try it again tomorrow to and from work and see if anything changes..but not holding my breath...thanx for the info...
 

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Discussion Starter #4
I cycled the heater today on the way to work...1 hour highway drive. The lower temps still seem to be cooler than they used to be. I am going to get a digital thermometer and check it that way...Tomorrow should be a good day to check it again...we are forecast to get 20-25 cm (10 Icnhes) of SNOW tonight...:surprise: May not be going to work since my snow tires have been off for almost a month...
 

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03 H6 OBW & 06 WRX Sportwagon
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what brand was the replacement t'stat - it matters


 

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Discussion Starter #6
what brand was the replacement t'stat - it matters


Replaced the old thermostat with an OEM thermostat...all parts that get replaced on our car get OEM replacements.
 
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@scoobydoo2

. . . thermostatwas replaced too. My temperature had been fluctuating and the air temps were a little wonky...lower temps than what was reading when set on Hvac. Today on trip to...from work the temp still fluctuates but at lower temps now...between 190.4C and 195 C.
Is the concern the 5 degree F. fluctuations, which, I understand, were present before the TB work, or is it the lower min/max range of the fluctuations with the new thermostat?

The lower range might be the new thermostat, especially if the previous one wasn't a Subaru part. Also, it's possible genuine replacements could have slightly different specs than factory-installed versions.

Fluctuations within a moderate range are not unusual; my 07, once fully warmed up, will usually highway cruise summer and winter at close to 87 C, even on hills, but in city driving it could go up three or four degrees, especially at traffic light stops in warm weather, and even higher if there's a long wait. (It will drop back to ~87 when I resume steady driving). I mentioned some of this in http://www.subaruoutback.org/forums...3-what-temperature-do-your-rad-fans-turn.html.

I'm not sure I understand the issue with the HVAC. I presume that's the automatic system where a temperature is set, and the system is supposed to maintain that temperature. Is it that the actual cabin temperature is always lower?
 

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Discussion Starter #8
@scoobydoo2



Is the concern the 5 degree F. fluctuations, which, I understand, were present before the TB work, or is it the lower min/max range of the fluctuations with the new thermostat?

The lower range might be the new thermostat, especially if the previous one wasn't a Subaru part. Also, it's possible genuine replacements could have slightly different specs than factory-installed versions.

Fluctuations within a moderate range are not unusual; my 07, once fully warmed up, will usually highway cruise summer and winter at close to 87 C, even on hills, but in city driving it could go up three or four degrees, especially at traffic light stops in warm weather, and even higher if there's a long wait. (It will drop back to ~87 when I resume steady driving). I mentioned some of this in http://www.subaruoutback.org/forums...3-what-temperature-do-your-rad-fans-turn.html.

I'm not sure I understand the issue with the HVAC. I presume that's the automatic system where a temperature is set, and the system is supposed to maintain that temperature. Is it that the actual cabin temperature is always lower?
My concern is more the Hvac. T’stat replaced the original...fluctuations were there with the old one. Engine Temps were 92-95 C. (192-201 F...ish) Now they are 88-94...ish

Hvac...I don’t use the auto function...I just set to what is comfortable. The lower temps 19 to 23-24 ish at times blow colder air while not on auto. That is what I am trying to figure out...why cold at warmer temps.
 

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My concern is more the Hvac. T’stat replaced the original...fluctuations were there with the old one. Engine Temps were 92-95 C. (192-201 F...ish) Now they are 88-94...ish

Hvac...I don’t use the auto function...I just set to what is comfortable. The lower temps 19 to 23-24 ish at times blow colder air while not on auto. That is what I am trying to figure out...why cold at warmer temps.
Thanks for the clarification. So, the issue isn't the engine cooling system, which is running at slightly lower temps, but the HVAC.

I don't have the Auto HVAC system in my 07, but I had a look at the 2011 Owners Manual (section 4). If I read it right, anytime the HVAC fan is turned on, the system is in one of two "auto" modes, and will seek to maintain the temperature(s) indicated on the display.

"The automatic climate control system
automatically controls outlet air temperature,
fan speed, airflow distribution air-inlet
control, and air conditioner compressor
operation. It activates when the fan speed
control button or the “AUTO” button is
pressed, and is used to maintain a
constant, comfortable climate within the
passenger compartment."

As I understand it, the default is a "Full Auto" mode, where all HVAC functions, e.g., fan speed, air outlets, recirc, and AC compressor operation, are controlled by the HVAC. However, if one of the HVAC-related controls is manually set, for example, if the fan speed control buttons are used to set the fan speed to one of the six available settings, then the system is in a reduced "Auto" mode. It will still function as before except that the fan speed (or whatever it was that was manually set) will not be adjusted automatically -- it will stay at whatever was manually set.

The system uses sensors for the cabin temperature, outside temperature, and sunshine hitting the windshield area, to determine how to operate. Just what logic is used is a puzzle, as there are other reports here of the automatic HVAC seeming to operate in strange ways. But it would seem that changes from the sensors could cause the system to react, perhaps overreact. (E.g., changing direction and strong sunlight suddenly hitting the upper dashboard area where the sun sensor is located.) Could this be a factor in what and when you are observing the colder air coming from the HVAC vents?
 
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