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my MY03 outback (gen3) has been using water (like 4L over 200km) and o/heats if i try to tow. i opened the bonnet and found one (LH, passenger) of the two fans wasn't working, even though the engine was real hot.

looking at the fan, it was crooked and i couldn't turn it by hand. i did also find that the 'main fan' fuse had blown. after replacing the fuse i could hear the motor come under load ever so slightly by putting in/taking out the fuse. the other fan (drivers side) would seem to come on with the A/C (not sure when else).

anyway, i took out the fan and find that it's been put on a bit crooked, and the fan motor has wrecker writing on it... replaced before.

first, i measured voltage at the plug (coming from the loom) and seem to get nothing, 0v (it's 4 pins but i have no diagram). then i put 12v across each pair of two pins on the fan and get a small spark but nothing else, nothing seems to kick in to spin.

i thought the engine would be hot enough to kick in the relay (which i think is ok after swapping them around) but i guess i could still have a wiring issue somewhere between the relay and the fan that i have to also address.

i think the fan motor is bust, and the fan too since it seemed to be put on incorrectly and chewed out the centre whole a little.

after speaking to the wrecker they reckon the LH (passenger) is for the A/C but this isn't my experience (i.e. the 'main fan' fuse seemed to make some difference, and taking out the sub-fan relay stopped the A/C fan from running). they did suggest it was possible someone has at one point swapped them (possible, since one has been out but the loom doesn't look as if it would allow it).

i tried ringing subaru, but they were no help ($600+ in parts alone, 'bring it in')

what i really want to know is:

LH fan is for A/C or radiator (this is a gen 3 I believe, May MY03 but before the engine model change that gave it a few more ponies).

the 4 pins on the plug - anyone know what they're for colour wise (i don't have/can't find a manual to buy online that i'm guaranteed will give me the answer, but i would buy one).

2nd hand i'm looking at ~$200 so don't really want to order the wrong thing (or find it doesn't solve my problem).

be great to hear from someone with the exact same car or with a good deal of experience in this area to confirm these few things so i can get the right part.

thx!

LH fan is for the AC. It is like that in my Gen 3 (only 2.5L but i believe its the same).

There are 2 fans, the main fan and the sub fan, each fan can operate at 3 speeds.
When the engine reaches about 97deg C, one fans kicks in in low speed with the air con off, if the air con is on, it bumps both of them up to mid speed, if the engine reaches 98 with the air con off, it runs them at middle speed. If the engine reaches 98deg with the air con on, it runs them at high speed.

Here is a diagram

Davidov wrote:LH fan is for the AC. It is like that in my Gen 3 (only 2.5L but i believe its the same).

No its not, the the 2.5L ECU chooses whether to run one fan on high, both fans on low or both fans on high, depending on engine temp and air con status. There is NO fan dedicated to just air con in either model.

This image is of the 2.5L radiator fan system, it does not apply to the original post

Using 4l water in 200km, if there's no visible water leaks its guaranteed the head gaskets are done.

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Gannon wrote:No its not, the the 2.5L ECU chooses whether to run one fan on high, both fans on low or both fans on high, depending on engine temp and air con status. There is NO fan dedicated to just air con in either model.

This image is of the 2.5L radiator fan system, it does not apply to the original post

Ah ok, i don't think ive ever seen my LH fan run, and was told by others. My bad.

thanks for all the quick responses.

i did consider the head gaskets, there is no other sign of water/oil mixing... and i guess i'm hoping for the best i guess it could be leaking into the cylinders...? only uses water when it gets really hot (and i end up letting off a lot of steam to get home)

can anyone confirm you can turn both fans by hand without the engine running? this is probably enough to at least confirm the fan i have out is stuffed/seized up.

"NO fan dedicated to just air con"

There is still a difference in the main and sub in other ways (power usage for example)?

You can emulate what the ecu does by grounding the 3 pins that control the fans. Id unplug the ecu first though. One pin will bring on one fan, another will bring both on and the third will turn them on high.
I should have explained clearer, it may be that the left fan comes on when the air con comes on, but both fans are controlled by the ecu. The left fan can still come on if the air con isn't on.

If you are using that much water, you are either loosing it out the tail pipe, or loosing it out your overflow bottle.

Sent from my new touchy phone thingy

Ok, so after all your tips (and to close this off) I find that it is indeed a faulty fan.

The LH fan motor (which is the 'main' or "cooling" fan in my MY03 3rd gen) was seized (you could not turn it by hand, or providing power to it didn't make it turn either). In addition, the fan blade was put on badly and this also needed to be replaced.

i managed to get a 1/2 decent price from a subaru dealer as it was dead stock. still stung me $400 to repair it and now the fan spins as expected. At least going to the dealer with part in hand allowed me to leave in confidence I had the right one - even the dealer could not 100% confirm which side was which!

here's hoping next time i need to tow something heavy it doesn't o/heat.