05 2.5i legacy with unusual engine rattle under load/acceleration

Found an '05 (2.5i) with 130K miles, for sale, feels nice and generally the car drives just fine but... under acceleration -- say up a hill where it's pulling a load and the rpms are heading up -- the engine emits a steady rattling noise that sounds like someone shaking an almost-empty can of spray paint, only faster. What is that? Phoned local Subaru dealer and their service manager speculated it's probably that the owner just uses cheap gas, or it could be valve slap etc etc. I neglected to check whether the car is burning oil but it didn't leave any clouds coming or going from my home.

 

My 2001 Outback has the same 2.5-L SOHC engine but no "rattle" and I'm not exactly averse to using cheap gas, myself...

I'm willing to bet its the same sound that had me a bit worried when I first got my legacy, and its completely normal. On my car, I'm pretty sure its most noticeable at around 2500rpm. The link below is a similar thread

http://legacygt.com/forums/showthread.php/boxer-sound-possible-probiii-new-09-2-5i-132257.html?t=132257

 

My advice would be to take it to a subaru dealer if possible and just try to see if they'll listen to it briefly. It's hard to say whether or not you should worry without hearing the sound.

Hi, though I describe it as a rattle, it's a very evenly spaced mechanical noise (like a machinegun), not random, more like part of the valve train or worse, some other vital revolving system. I wasn't able to pinpoint whether it only occurs in a specific rpm band, and probably won't be able to take it into the dealer, considering the seller lives out of town and made a trip in (twice actually) just to let me test-drive it.

 

Granted all the gruesome possibilities (piston slap, worn crank bearing, etc) this might be a dealbreaker. I guess I at least owe the seller a tip for his troubles....

While I love my 7 year old digital camera, it doesn't have the best movie mode. Nonetheless, I still tried to capture the sound my car makes, which is the same sound I believe you're talking about. Not the best clip, but I can definitely pick out the sound in certain parts. I'm basically in 1st and 2nd gear, trying to hold and blip the throttle at around 2400rpm to 3100rpm, where I notice the sound the most.

 

apexi, thanks for the assist here. Your recording still sounds within "normal" range to me, or it could be that my move-player or PC just don't reproduce the audio well; the car I test-drove had a more metallic clap to its rattle that kicked in when the car was accelerating up a hill about 60 mph in 3rd (sportshift) and again on a much steeper backstreet about 20-25 mph in 1st gear. Best I could tell it may have been anything above 3000 rpm. Further, the rattle was in sync with engine speed so I don't think it was anything non-engine related....

 

Oh well, I backed out of the sale. The car might not have any mechanical problems at all, but I couldn't live with a rattle like that. Would've been a sweet deal to me if that car only purred or screamed like my fatass Outback wagon or the couple other Suberooz I've driven lately.

 

I'm trying to find a local Legacy or Impreza sedan, 05 or newer, but people are holding onto theirs (lots of 1st and 2nd gen Outbacks available but no sedans....).

If it only happens under heavy load it may be the engine pinging. It's hard to tell without actually hearing the noise though.

^ that would be my suspicion too