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Cause of higher pitch sound when accelerating after 90K servicing by dealer?


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This is one I’ve been wondering about for a while, though not related to any problem I’m aware of. After our 90K servicing, which is a major service, and which we did at the Subie dealer, we heard a bit more noise, and higher pitch noise (bit of a whine), whenever accelerating. The engine was just a bit louder and higher pitched. What would cause this, and is it something that needs attention? The car was quieter and smoother sounding before the 90K servicing. You would think it would sound smoother after the service.

 

Car is a 2003 3.0 L H6 VDC Outback 2003 in excellent condition, at 105,466 miles. About to perform the 105K inspection and servicing, which is a minor servicing, during which we can look into the issue.

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some possibilities;

 

tabs on lower part of intake filter box not seated in slots (usually more of a whooshing sound)

 

 

serpentine belt tensioner and/or idler pulley bearings going bad (known problem)

 

 

air being sucked into PS pump at fitting on top that suction hose from tank is connected too. (known problem)

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Sounds more like a mechanical noise than a whooshing noise caused by air flow.

 

Most likely a tight belt or idler pulley bearings. Could a belt stay tight like that for a year? Basically ever since the service the engine sound when accelerating is a bit higher pitched because of that bit of a whine, which does sound like it's related to a fan.

 

What are the idler pulley bearings, and are they difficult/expensive to replace?

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Well, something isn't right.

 

Maybe they drained the front diff and forgot to refill?

 

Does the whine seem to increase by the same amount as the increase in vehicle speed, or does it seem to increase 4x 'faster' than the vehicle speed?

 

Dave

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I had a truck once (non-Subaru) that made more engine noise after a servicing... it turned out that the pulleys (crankshaft, alternator, A/C, etc) were slightly misaligned, and the old serpentine belt was quieter because it had worn down to accommodate the misalignment, masking the problem until I got a new belt. :rolleyes:

 

Just throwing that out as a possibility, but I'm not sure that this situation would persist for 15k+ miles...

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Dave, whine increases at same rate as acceleration. This isn't a very loud whine, it's subtle - many casual drivers would miss it, but I always pick up on the slightest change in a machine. Used to sound fully smooth before, and now it just has this subtle higher pitch whine - I'm fairly sure it's related to the fan.

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the radiator/AC fans are electric.

 

My wife's OBW got a little quieter when i put synthetic fluid in the front diff. perhaps, if the dealership seviced the front diff, the previous owner had a heavier weight/'different' oil in there and the Subaru fluid is allowing it to sound a little louder. Or maybe they failed to top it up.

 

Have you checked the front diff's fluid level?

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Someone else posted this & I also replied, because I have the same, mine sounds like a turbo, when accelerating, but I dont have a turbo. No one seemed to have an answer.

 

95-99 EJ22 cars had this problem...it was the air box design...customers complained enough, so in 2000 they baffled the crap out of the air box, and changed the filter location to the top of the throttle body.

 

Personally I love the sound of the 95-99 accelerating...I always romp on it, just to make that "turbo" noise...then again I come with a weighted right foot.

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95-99 EJ22 cars had this problem...it was the air box design...customers complained enough, so in 2000 they baffled the crap out of the air box, and changed the filter location to the top of the throttle body.

 

Personally I love the sound of the 95-99 accelerating...I always romp on it, just to make that "turbo" noise...then again I come with a weighted right foot.

 

Cool! Resell the old boxes to the kids with the big fart cans on the exhaust tips!

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