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'06' Outback 2.5i w/ 5MT; '98' Forester L w/ 4EAT; 2017 Volvo XC60 T5
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Discussion Starter #1
Hello everyone,

I wanted to add my $.02 regarding the cooling fan issues that appear to be a trend beginning around MY '05' or so. "Plain OM" and "Cardoc" have made some very good threads/posts on this topic. "Plain OM" has many posts that will help you to understand the circuitry of the fan system and how to troubleshoot the relays.

"Cardoc's" insight/observations explain my situation. I have an '06' Outback 2.5L N/A. Here is my story/experience regarding the OE cooling fans. This is kind of a long-winded comical recounting, so if you want the conclusion simply scroll down and read the bottom paragraph.

A little over 3 years ago (early 2011), after coming back from an 800 mile road trip to the mountains (where my car was buried in about 5 feet of snow for a few days), I heard one of the fans short-cyling on/off at high fan speed when the defrost was on. Popped the hood and found the main fan short-cycling at high-speed (on for a second or two, off for a second or two) and the sub-fan not running at all. You would expect both fans to cycle on/off at low-speed in sync with the AC compressor. Removed both fans and jumped them directly to the battery - main fan motor was good, sub-fan motor was bad. Tested for resistance across the bad fan's plug terminals and sure enough there was an open circuit. Figured I may as well tinker and learn something, so completely disassembled the sub-fan motor, cleaned everything up (commutator, winding, brushes, etc.), reassembled and voila, resistance was back down and the motor ran like a champ when jumped. Put the fans back in and gave myself a pat on the back for fixing it without having to buy a new fan. Odom. was at about 60,000.

System operated perfectly for the next year, until I went back up to the snow and got the car buried by a classic Sierra Nevada 5-foot dump again! Sure enough, sub-fan motor had gone bad again after the snow burial. Figured this darned fan just didn't like being buried in the snow. Did the exact same thing when I got home - took the fan motor apart, cleaned, reassembled and it ran great again. This was in 2012 with the odom. at about 70,000.

System operated perfectly from 2012 - 2014 (no snowboarding trips due to the last 2 winters being terribly lacking here in California).

Just last week as I was taking my wife and 3 kids on a road trip through southern Arizona on our way to Puerto Penasco, Mexico, I noticed my temp. gauge edged up a tad over the normal "slightly below mid-point" setting that we have all become so familiar with (and appreciative of!). This was with the AC running and outside air temp. at 114 degrees. Only lasted for about a minute before coming back down to normal, so I didn't fret too much over it - but given that I had just flushed the cooling system and changed the coolant before the trip, I did find it odd that it went above normal at all since we were cruising along on a level highway at 70 mph with a ton of airflow through the radiator fins. Temp. gauge did not rise above normal again for the remaining 300 miles to our destination. On the 700-mile trip home, I noticed the temp. gauge creep up slightly again when we were stopped and idling at the border - at this point I realized I had lost a cooling fan (again). Drove the entire 700 miles home with the AC on and no issues (temp. gauge rose slightly above normal two times before coming right back down again, but we were lucky and didn't hit traffic going through LA, so had plenty of airflow through radiator the entire time). Car now has 88,000 on the odom.

Just looked at it today, and this time the main fan motor has gone bad, while my twice-disassembled and repaired sub-fan motor is still running great. Main fan motor had an open across the terminals. Spun the fan a few times by hand and what do you know resistance came back down, jumped the fan to battery and it spun like a champ, reinstalled in the car and both fans are operating normally again.

CONCLUSION: My sub-fan motor fails when subjected to cold conditions. My main-fan motor fails when subjected to hot conditions. The fan motors will not start working again until you physically tinker with them. These OE fan motors (or at least the fan motors on my car) appear to be fickle little buggers that easily develop an internal open circuit when stressed with temperature extremes. I am tired of pulling my fans (3 times now with the odom. only at 88,000), and am throwing the towel in on the Subaru OE fan motors - new Dorman main-fan and sub-fan assemblies can be had on Amazon or RockAuto for about $70 each, and are on their way to my house.

If one or both of your fans are behaving strangely or not turning at all, I would recommend 1st jumping them directly to the battery to check the motors before you do anything else, as I have a feeling the OE fan motors from the '05' - '07' era have a high rate of failure.
 

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Silver 06 2.5i
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696 Posts
Same problem with my 06 outback. Did not do the redo of motors just replaced both intire fan assembly, plug and play from rock auto dorman fans.
 

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OB Fans/Overheating

I saw the thread in strange fan problems relative to cold and hot. I have 100 k on 2006 OB! 2.5. I noticed neither fan running even when pushing ac on. I controlled engine temp with heater. I replaced main fan relay and behold, I push the ac and one fan comes on and cycles. I have not witnessed the other fans running. I think this is odd. The one that runs in the drivers side. Engine temp seems to be fine now, but I have not experienced a hot day since replacing the relay. Does anyone have anything to add regarding how these fans work. Should they both come on? Thanks.
 

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Yes, non Turbellaria. Push ac button, ac works fine but only 1 fan. I just wondered if the other fan would come on only if required because of the temp.
 

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No, both fans all the time. However, the fans can be run at a relatively slow, or high speed. For slow, a set of relays controlled by the engine control module connects the two fans in series; for high speed, each is connected individually to the 12 V power source. When set for low speed, if one fan motor is open circuit, neither will run; if set for high speed, the bad motor won't run, but the good one will.

Here's a recent thread with similar symptoms where there's more info on the wiring circuit and operation: http://www.subaruoutback.org/forums/80-electrical-electronics/165890-fuse-question.html
 

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'06' Outback 2.5i w/ 5MT; '98' Forester L w/ 4EAT; 2017 Volvo XC60 T5
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252 Posts
Discussion Starter #8
I saw the thread in strange fan problems relative to cold and hot. I have 100 k on 2006 OB! 2.5. I noticed neither fan running even when pushing ac on. I controlled engine temp with heater. I replaced main fan relay and behold, I push the ac and one fan comes on and cycles. I have not witnessed the other fans running. I think this is odd. The one that runs in the drivers side. Engine temp seems to be fine now, but I have not experienced a hot day since replacing the relay. Does anyone have anything to add regarding how these fans work. Should they both come on? Thanks.

As "Plain OM" said, both fans should always come on together, never only one. Your sub-fan motor (passenger side) may very well be bad - try jumping it directly to the battery, per my original post above. If one fan motor is bad, what happens when you turn the AC (or defrost) on is there will be a time lag between when the AC compressor engages and when the remaining good fan comes on, and when the one good fan does come on it will come on at high-speed. As "Plain OM" said, the fans are wired in series when at low speed, so when the ECM calls for low-speed fan operation one bad fan motor will result in both fans not turning. I think the way it works is when the ECM calls for low-speed operation, but then detects an open in the fan circuit (due to the bad fan), it switches the relays to call for high-speed operation, which then kicks the good fan on at high speed.

If your main fan (driver's side) is short-cycling on/off at high speed with the AC or defrost on, there is a good chance your sub-fan (passenger side) has a bad motor.
 

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Well. most of fan motor failure is worn out of carbon brush or dead spot on commutator.
open up motor and you will see the condition of brush (Usually ,reuse after cleaned contacting place (both brush and commutator).

Before ,you do this you have to find the problem on motor.
 
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