Thanks for helping with my diagnostic!

 

I just bought a '03 Impreza Outback Wagon last week with 106k and an auto tranny. Everything on the car is great (well one CV boot needs replaced, but hey, it's a subie ;-) Shifts well, cold AC, little rough on the idle, but not bad.

 

Here is the issue. While driving around town with the AC on, 'bout every minute, there is a sound like a sneezing cat, Driver's side, just forward of the seat. UNDER THE CAR. The sound could also be described as running over a soda can with the left front tire that had already been run over (flattened). The first few times it happened I thought "hey, ran over a flattened can. Hey, ran over another flattened can. Hey...wait a sec..." It is a very quick "thrack" and then nothing for another minute or so. Happens regardless of torque, grade or speed.

 

The car does seem to bog VERY slightly when ever this happens.

 

A new discovery today was that the same effects happen without the AC on--while the blower fan in on w/o the AC engaged.

 

Any thoughts and ideas welcome!

Edited September 27, 200817 yr by melvin-98
better discription

I had a Leggie that had a similiar problem. I pulled the blower motor, which is inside the cabin, in front of the passanger seat, behind the glove box, against the fire wall. I pulled out the blower motor thinking it was going bad, only to find it clogged with tree leaves and crud. I cleaned out the junk, reinstalled, and the blower ran fine again. I think you may have a similar situation. It was very easy to pull the blower motor on a Leggie, so prolly so an Imprezza.

Humm, that is an idea, but the sound is emanating more from under the car. When I have had just blower fan problems, the sound has been in the cabin on the right side. And there there is the issue of engine bog.

 

It is VERY uniform. It is always the same sneeze, for the same duration. When you first turn the blower on it ALWAYS does it. It has that metallic quality of the runover can, not so leaf-rattle like.

 

THANKS for your thoughts!

 

I think I will start by looking for crud in the housing though, that is a good start!

maybe something going on with the ac clutch... sounds like that noise that happens when the compressor kicks in, but it's odd that's it's happening when the ac is off, unless it's not really fully off...

 

 

--Spiffy

So could I yank the AC fuse to get it to be "fully" off?

 

Clutch was my first thought too, right up until we turned the AC off and it still sneezed...

Anyone have any ideas if the compressor is still engaged even though the AC "button" is off?

 

I know that sounds odd, but I can't think of any place else this sound is coming from!

Anyone have any ideas if the compressor is still engaged even though the AC "button" is off?

 

I know that sounds odd, but I can't think of any place else this sound is coming from!

 

 

 

Some cars will run the compressor during defrost, even if the A/C is turned, but I don't know if Subbie does that. Suggest disconnecting the power wire lead going to the compressor at the connector right at the compressor. That way, you know for absolute sure that the compressor can't operate.

Clever! I will do just that and let you know. Thanks for your help!