fan speed decreasing after long drives
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Joined: May 2003
Posts: 6
fan speed decreasing after long drives
Anybody had this problem? The fan stops blowing hard after I've been driving my wrx (2002) for about 2 hours in a row. Even when I crank the thing up to 4, it feels like it's blowing on 1. The A/C still seems to be working, b/c the air that is blowing seems cold.
The funny thing is when I turn it up, the fan noise gets louder as if it should be blowing harder and faster, but I can hardly feel the air coming out of the vents.
If I let the car sit for a couple of hours, everything goes back to normal, and the air will really crank when I turn the speed up to 3 or 4..
Any ideas?
The funny thing is when I turn it up, the fan noise gets louder as if it should be blowing harder and faster, but I can hardly feel the air coming out of the vents.
If I let the car sit for a couple of hours, everything goes back to normal, and the air will really crank when I turn the speed up to 3 or 4..
Any ideas?
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Joined: Nov 2002
Posts: 1,646
From: NYC
Car Info: 02 WRX WRB
Your AC is freezing up. Ice forms on the evaporator and blocks the air flow causing less air to come out of the vents.
This typically happens on long drives. A temporary fix when it happens is to turn the AC off and keep the fan going, after a while the ice will melt and flow will return to normal.
There are service bulletins about this problem for WRXs that fall within certain production dates, you should contact your dealer and inform them you have experienced your AC freezing up.
This typically happens on long drives. A temporary fix when it happens is to turn the AC off and keep the fan going, after a while the ice will melt and flow will return to normal.
There are service bulletins about this problem for WRXs that fall within certain production dates, you should contact your dealer and inform them you have experienced your AC freezing up.
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Agree with the A/C freeze up assessment. I'd check that too.
BTW - Do you have the optional air filtration system (replaceable filters)? Depending on your driving conditions, these tend to collect a lot of airborne crap (like they're supposed to do) and once they've reached their saturdation point, your airflow is significantly reduced too. On my wife's Forester, we found that as the filters got more clogged, initially, the airflow starts out reasonably fast and then decreases as the fan pulls the particles further and further into the filter thus reducing the airflow. These need to be changed about every 12 months or more often if you drive your car in dirty air locales.
Br, Dale
BTW - Do you have the optional air filtration system (replaceable filters)? Depending on your driving conditions, these tend to collect a lot of airborne crap (like they're supposed to do) and once they've reached their saturdation point, your airflow is significantly reduced too. On my wife's Forester, we found that as the filters got more clogged, initially, the airflow starts out reasonably fast and then decreases as the fan pulls the particles further and further into the filter thus reducing the airflow. These need to be changed about every 12 months or more often if you drive your car in dirty air locales.
Br, Dale
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Joined: May 2003
Posts: 14
Car Info: MY02 RS, 5MT
swiftsoles --
I experienced exactly the same situation a few times except that as I recall, the fan started blowing again after giving it and the AC about a half hour rest. It was always pretty hot weather.
I asked the dealer about this and was told no one in the shop had heard of it. He said he'd plug the info into some national database deal he said Subaru has and would contact me if anything turned up. Haven't heard from him.
I hope you'll post back how the fix goes. I basically hate for anyone to touch my car and have the fear that the dealer will want to let the thing idle for 2-3 hours in an attempt to reproduce the situation before doing the repair. Nice thing about these forums is you can say obsessive things like that and more people understand than don't.
I experienced exactly the same situation a few times except that as I recall, the fan started blowing again after giving it and the AC about a half hour rest. It was always pretty hot weather.
I asked the dealer about this and was told no one in the shop had heard of it. He said he'd plug the info into some national database deal he said Subaru has and would contact me if anything turned up. Haven't heard from him.
I hope you'll post back how the fix goes. I basically hate for anyone to touch my car and have the fear that the dealer will want to let the thing idle for 2-3 hours in an attempt to reproduce the situation before doing the repair. Nice thing about these forums is you can say obsessive things like that and more people understand than don't.
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Joined: May 2003
Posts: 6
I took the car into the dealer today concerning the problem. It was the evaporator freezing up. I don't know how long they had to let it sit idling with the A/C running. I would hope not long. They should be able to tell if the compressor is switching on and off appropriately.
To fix the problem, they moved the Thermosensor on the evaporator. I guess it wasn't in the right position. I read the service bulletin concerning this problem, and the resolution was to replace the Thermosensor, but apparently this dealership thought moving it to a different location would be better. I had to have a late pickup on the car since I work late, so I wasn't able to talk to the service representative when I picked it up.
I probaly won't drive it for any extended period of time until next weekend, so I won't know for sure it's fixed until then.
To fix the problem, they moved the Thermosensor on the evaporator. I guess it wasn't in the right position. I read the service bulletin concerning this problem, and the resolution was to replace the Thermosensor, but apparently this dealership thought moving it to a different location would be better. I had to have a late pickup on the car since I work late, so I wasn't able to talk to the service representative when I picked it up.
I probaly won't drive it for any extended period of time until next weekend, so I won't know for sure it's fixed until then.
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Joined: May 2003
Posts: 14
Car Info: MY02 RS, 5MT
Thanks for the update.
Did you read the service bulletin at the dealer's or the Acrobat file download on the Subaru tech info site?
Where is the thermosensor? Where did they move it to? Do you or any of the pros out there think the daring novice might safely reposition it?
Did you read the service bulletin at the dealer's or the Acrobat file download on the Subaru tech info site?
Where is the thermosensor? Where did they move it to? Do you or any of the pros out there think the daring novice might safely reposition it?
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