Have a 2004 WRX w/about 133,000 miles on it. Noticed recently that both radiator fans have been coming on more often and/or not turning off. The temp. gauge never goes above half way so the engine doesn't appear to be over heating...and it's also been real cool here and I have not been running the AC or defrost. And when I say both fans come on, they come on full blast and are kind of loud. Last time I noticed it happening was when I recently pulled into my garage so it was easy to tell they were on. Instead of turning the car off, I let it sit there and idle to see if they would turn off on their own. Even put the hood up to help. Let it idle for about 5 minutes and they still didn't turn off. The outside temp. was probably mid-60's at the time.
I've searched around and the only thing I found close to what's happening with my car was in a Legacy GT forum and in most cases it turned out to be the ECU and/or fan relay. There was a TSB/recall for it but it only covered certain 2004 (maybe 2005 too?) Legacy and Outbacks. Could there be a similar problem with the WRX ECU's?
This past summer my radiator cracked while we were out. It didn't loose a whole lot of coolant and we were able to drive it home without it overheating. The fans both came on (like they should) by the time we got home (temp gauge never went above half way the whole time). Ever since then (and having the radiator replaced) is when I seemed to notice the fan issue more often. Not sure if there's a relationship there or not.
It seems to be more of an annoyance than anything right now, especially since the car doesn't appear to be over heating at all and the coolant level is more or less consistent. But I suppose the fan motors could fail quicker and I'm not sure if this would cause problems this summer when the AC will be in use. The other forum suggested things like removing the fan fuse so it turns off. Don't really want to do that. Would resetting the ECU help? Or should I just take it to my mechanic and see if they can find something. I really don't want to pay for a new ECU.
Any help/suggestions would be greatly appreciated. Thanks.