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Discussion Starter #1
Ok ppl, what I know up to now :
  • t-stat opens up at 91C, fully opens at 98C
  • radiator fans low speed fires up at 102C . high speed at 105C
So I guess the "intented" nominal temps must be somewhere 91 and 98, with 100+ being in the "exception" - "upper margin" range. So on the highway, what temps do you observe under various loads and conditions? I observe from 91-92C e.g. on downhill with low engine load, up to 102C, uphil , high engine load.

What's your experience? Should I be worried? Is there anything wrong with my own car? Or maybe there is a "glitch" by design somewhere ?
 

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If you worry that it can overheat there are some working solutions. 1st you can install auxiliary electric fan in front of the radiator. Measure the radiator and you can get a fan which is both pusher/puller. If you don't have space, you can get performance radiator which is 3-4 times more expensive sometimes of the OEM one (depends). The fan is easier, because it can run on a t-stat or with a manual switch. I am thinking of installing such twp fans which have 8 inch blades, and they will be located in front of the radiator. (Like putting Hella Horns) ;)
I have seen from my experience that some cars are designed like that. My t-stat opens at 78 degrees. It is a Magneti Marreli. You can ask some shops or look into google for such t-stats with lower temperature settings.
 

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Discussion Starter #3
Yes I am afraid this is the design. It's all due to emissions. Newer cars (I mean >=2009) are running hotter at idle in order to meet specific standards regarding emissions.
Installing a coller t-stat would be a start, but also the fans should kick in earlier as well.
I also have a AC whose condenser sits in front of the radiator. Also mine has two biggy fans.
Hmmmm maybe custom fans? newer fans?
although the key is the temperature.

I mean I have a hyundai i20, whose t-stat opens between 86-93 and fans kick in at 97, so max temp is 97.

So if you follow this you'll see there is a pattern persistent in both cars/maps:
98-91 = 7
93-86 =7
98+4 = 102
93+4 = 97

So the ideal would be to program the map regarding radiator fans, but this is impossible for NA subarus (BRZ ad some american models aside)
 

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Do you have a workshop manual to double check those figures?

Looking at the workshop manual for the 2007 it says:
Starts to open:
Non-turbo model
80 — 84°C (176 — 183°F)
Turbo model
76 — 80°C (169 — 176°F)
Fully opens:
Non-turbo model
95°C (203°F)
Turbo model
91°C (196°F)

Looking at the aftermarket options for a 2007, they all seem to open around the 172 F mark. Which seems sensible.

I don't have a 2009 or 2010 manual to look up for you, but looking at the aftermaket thermostat options for a 2009 onwards, they still seem to be rated for 170F / 78, making me think your numbers might be a little out ? Sounds like your thermostat should be fully open before your stated 98C - Even with emissions

Have you tried running a colder opening thermostat to see if that helps? I guess maybe not if you are running hot enough to trigger the cooling fans.

Are you positive there is no blockage in your radiator and it is in good condition ?

There is always the alternative option...... Sell the SH Forester and get an SG Turbo Forester - No cooling issues with those ;)
 

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Discussion Starter #5
Hello TMX,
yes I have the workshop manual. The numbers I gave are from the manual and also verified from the car's behavior. SG is different than SH as you have noted.
Yes, I am positive there is no blockage since the radiator , hoses, coolant, t-stat are all replaced, in the interval of the last 2 years.
That's why I ask ppl with the SH N/A 2.0 to give me their numbers while running in the highway. (I ask about the highway, cause in the city , idling , etc the behavior is pretty much standard and described by the radiator fans temperature : (low speed) 102C, and very very very rarely (high speed) 105C.
 

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Discussion Starter #6
• DOHC Non-turbo model
Vehicle speed​
A/C compressor load​
Engine coolant temperature​
Increase: 101°C (214°F) or less
Decrease: 101°C (214°F) or less​
Increase: 102 — 103°C (216 — 217°F)
Decrease: 102°C (216°F)​
Increase: 104°C (219°F) or more
Decrease: 103°C (217°F) or more​
Radiator fan operation​
Radiator fan operation​
Radiator fan operation​
During acceleration: 19 km/h (12 MPH) or less
During deceleration: 10 km/h (6 MPH) or less​
OFF​
OFF​
Low-Speed​
High-Speed​
Low​
Low-Speed​
Low-Speed​
High-Speed​
High​
High-Speed​
High-Speed​
High-Speed​
During acceleration: 20 — 69 km/h (12 — 43 MPH)
During deceleration: 11 — 64 km/h (7 — 40 MPH)​
OFF​
OFF​
Low-Speed​
High-Speed​
Low​
High-Speed​
High-Speed​
High-Speed​
High​
High-Speed​
High-Speed​
High-Speed​
During acceleration: 70 — 105 km/h (43 — 65 MPH)
During deceleration: 65 — 100 km/h (40 — 62 MPH)​
OFF​
OFF​
Low-Speed​
High-Speed​
Low​
OFF​
Low-Speed​
High-Speed​
High​
Low-Speed​
High-Speed​
High-Speed​
During acceleration: 106 km/h (66 MPH) or more
During deceleration: 101 km/h (63 MPH) or more​
OFF​
OFF​
OFF​
High-Speed​
Low​
OFF​
Low-Speed​
High-Speed​
High​
OFF​
Low-Speed​
High-Speed​


Cooling system​
Electric fan + Forced engine coolant circulation system​
Total engine coolant capacity​
MTSOHC model
L (US qt, Imp qt)​
Approx. 6.8 (7.2, 6.0)​
DOHC Non-turbo model
Approx. 6.9 (7.3, 6.1)​
ATSOHC model
Approx. 6.7 (7.1, 5.9)​
DOHC Non-turbo model
Approx. 7.3 (7.7, 6.4)​
Water pump​
Type​
Centrifugal impeller type​
Discharge performance I​
Discharge rate​
L (US gal, Imp gal) /min​
20 (5.3, 4.4)​
Pump speed — Discharge pressure​
760 rpm — 2.9 kPa (0.3 mAq)​
Engine coolant temperature​
80°C (176°F)​
Discharge performance II​
Discharge rate​
L (US gal, Imp gal) /min​
100 (26.4, 22.0)​
Pump speed — Discharge pressure​
3,000 rpm — 49 kPa (5.0 mAq)​
Engine coolant temperature​
80°C (176°F)​
Discharge performance III​
Discharge rate​
L (US gal, Imp gal) /min​
200 (52.8, 44.0)​
Pump speed — Discharge pressure​
6,000 rpm — 225.4 kPa (23 mAq)​
Engine coolant temperature​
80°C (176°F)​
Impeller diameter​
mm (in)​
76 (2.99)​
Number of impeller vanes​
8​
Pump pulley diameter​
mm (in)​
60 (2.36)​
Clearance between impeller and case​
Standard​
mm (in)​
0.5 — 1.5 (0.020 — 0.060)​
Thermostat​
Type​
Wax pellet type​
Opening start temperature​
SOHC modelEngine side
80 — 84°C (176 — 183°F)​
DOHC Non-turbo modelEngine side
89 — 92°C (192 — 198°F)
ATF warmer side
69 — 73°C (156 — 163°F)​
Fully opens​
SOHC modelEngine side
95°C (203°F)​
DOHC Non-turbo modelEngine side
98°C (208°F)
ATF warmer side
84°C (183°F)​
Valve lift​
Engine side
mm (in)​
9.0 (0.354) or more​
ATF warmer side
mm (in)​
8.0 (0.315) or more​
Valve bore​
mm (in)​
35 (1.38)​
Radiator fan​
Motor input​
Main fan​
90 W​
Sub fan​
90 W​
Fan diameter / Blade​
Main fan​
300 mm (11.81 in)/4​
Sub fan​
300 mm (11.81 in)/5​
Radiator​
Type​
Down flow, pressure type​
Core dimensions​
Width × Height × Thickness​
mm (in)​
687.4 × 340 × 16
(27.06 × 13.39 × 0.63)​
Pressure range in which cap valve is open​
kPa (kg/cm2, psi)​
Above: 108±15 or more
(1.1±0.15, 16±2)
Below: −1.0 to −4.9 or less
(−0.01 — −0.05, −0.1 — −0.7)​
Fins​
Corrugated fin type​
Reservoir tank​
Capacity​
L (US qt, Imp qt)​
0.45 (0.48, 0.40)​

Recommended materials​
Item number​
Alternative​
Coolant​
SUBARU SUPER COOLANT (Concentrated type)​
—​
Non-amine type​
SUBARU SUPER COOLANT (Diluted type)​
K0670Y0001​
Water for dilution​
Distilled water​
—​
Soft water or tap water​
 

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So this is the metal fan, which runs on 12V, I have ordered 2 of them with 8 inch blades. They have ball bearing and the fan is made from mostly metal (almost everything). Also remember that the big fans on general cars runs from 2000-4000. Also it is very imporant from what kind of material the fan and the body are made. Most of the modern cars have plastic parts, which is cheaper to make but they do not last that much.

522990


I will have to change the cables because the radiator heat is quite a lot for the current thin cables. So the idea is 2 of these, put behind the grill, placed on the radiator. Both of them could be pusher/puller. I will have to make a manual switch which will have a potentiometer so i can regulate the RPMs of the fans and to be able to turn them ON/OFF. I will start working on this idea the next 2 weeks.
I stole this idea from a friend of mine who has a Opel Astra and he bought a radiator, which was made from plastic and aluminum and he had some issues with the heat. So when he installed 1 fan and there was a difference.
 

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Discussion Starter #8
Hi I know my fans are 2-speed, but cannot quite grasp the push/pull theory. Care to explain a little bit?
 

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Yes sure. So the push/pull method is the direction of the air flow TO or OUT of the radiator. Even 1 fan can have both ways of air flow. I attach you a link of the American product, the guy explains it pretty well the work of the Auxiliary fan. As you can see his is made of mostly metal parts. I write it again, if you put such fan or fans, you need metal ones only. The consumpiton you can calculate easy how much you will need for each fan. The potentiometer will regulate the RPMs of the fan. Of course do not expect high RPMs, like 4000... For me it is quite impossible or IF the fan cost 100 $ at least. When you get a metal fan for 50$ it will go IMO at least at 2000-2500 RPMs, which is OK. For me that is enough.

 

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Discussion Starter #10 (Edited)
I was looking at the fans yesterday and a little bit on the wiring diagram. What I saw was that both fans are pulling air from the outside towards the engine, I mean placing my hand in front of them (between fans and engine) I feel the air. I also saw that the two speeds are implemented via parallel/series wiring. In-series for low speed, parallel for high speed.
 

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Discussion Starter #11
Assuming that there is no place for additional fans, I mean there is the AC condenser in front of the radiator, what would be a decent upgrade? New replacement fans that work the same way but are larger and faster?
 

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Upgrade? How about spraying the radiator down with a cleaner,sopa,detergent then rinsing with moderate high pressure water from the inside towards the front.

May want to remove the fans for easier access and rig up some sort of U- TURN fitting on the end of the hose, prior to the high pressure nozzle , to make this easy.
 

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...purpose being to rinse out the dead bugs. The AC condenser will have to be dealt with, somehow.

Ever removed your radiator? Then you could clean the condenser as described above, and the radiator with ease since it would not be in the car.

. You would have to deal with the coolant, though, if you used a clean container, and could cleanly drain, I do not see why you could not just put the same coolant back in.
 

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Discussion Starter #14 (Edited)
Thanx for the suggestion. The radiator is a new KOYO, was fit in Spring of 2018, along with new hoses. Coolant, T-stat (OEM), cap (OEM) were changed in 2017, so they're 2 yrs old. I have never done such work as uninstalling the radiator, fans, etc. I am good(ish) in theory but have no garage, no equipment and no friends to do such tasks.
(and my wife won't be particularly happy if she sees me doing such stuff, she's the kind of person that thinks German cars are unbeatable, her best friend's Toyota engine was blown so now she thinks japanese cars are junk).

Anyways, Car maxed 104C (219F) in Serbia (some weeks before) at a toll station while idling so within limits. Also I got 102C uphill this Monday returning from my home town.
I dont know if am getting overly paranoid here. Could be, but I can feel it when the car has a problem cooling down, so , its not only my idea.
But you know I would like to never see temps above 100C on the highway. I would love to get over this once and for all. To be free to hit the gas all the way down without fear of overheating.
 

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Discussion Starter #15
So ppl, what are your average/min/max highway coolant temperatures?
Have you got some digital gauge to monitor the temperatures ?
Or are you relying on the temperature light to go blinking red?
 

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I was looking at the fans yesterday and a little bit on the wiring diagram. What I saw was that both fans are pulling air from the outside towards the engine,
You could put a fan in front of your AC condenser to push air through towards the engine

. Wired to a thermostat and relay, or switched on via a relay and manually controlled by you from inside the cabin, it should help your ac from baking your radiator behind it as well as provide extra airflow to the rad.

Is the condenser "buggy"?
 

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Discussion Starter #17
You could put a fan in front of your AC condenser to push air through towards the engine

. Wired to a thermostat and relay, or switched on via a relay and manually controlled by you from inside the cabin, it should help your ac from baking your radiator behind it as well as provide extra airflow to the rad.
That's a great idea. A first glance it seems that there is some room in there, between the grill and the condenser.

Is the condenser "buggy"?
Yes, I just looked. It doesn't look particularly clean, but not awful either. I'll to post a photo.
 
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