Engine Rattle From 2k-2.5k RPM

Lately I've really been noticing a rattling sound that seems to be coming from the engine when the tach reads between 2000-2500RPM. I only hear it in that range, but not before or after.

 

To hear it clearly I need to turn off the radio and the climate control--it's not that loud at all, but definitely noticeable. I think I can only hear it if the car is warmed up.

 

I tried to see if it is gear specific tonight but I couldn't hear anything over the rain. If I rev that high in park, then I can't hear it. If I'm in drive, then I can hear it (even if I'm sitting still with the brake on).

 

Any ideas what it could be?

got any mods, aftermarket exhuast....?

No, but I've heard this sound in my STi in the same rev range, and also in my wife's OBXT this past weekend. I was worried about it when I had only heard in in the STi; hearing it in the Outback led me to believe it's one of those 'normal' sounds.

 

It almost sounds like a sticky valve to me, but both cars have < 16,000 miles and get regular oil changes. The noise goes away as revs climb or drop out of the 2-2.5k range as noted above. The noise is also at a consistent rate. A noisy valve should tap faster and slower as revs climb and fall.

got any mods, aftermarket exhuast....?

Nothing. Even the stock tires.

 

Almost 10,000 miles on the car, regular maintenance.

bring it to the dealer for warrentee.

Heat shield's more than likely. Plus boxer have a unique sound all in themselves. I had someone rev mine up on a lift till I found culprit(s). My solutions are expensive, new headers with built in uppipe, downpipe and complete exhaust, so far I've only bought the downpipe. The rest is only a click away. "Build it....and they will come"

that sounds exactly like one of my baja's problems. It has been to the deliership 4 times now with no fix. each time it seems fixed, but after about 100 miles, it is back. It started nice and quiet like you are saying, but has gotten so loud that I can hear it in an intense down pore with the sterio blasting to compensate for the rain, and the heater on full. so anoying. The master tech said that he is now clueless on where it is coming from. They just replaced the timing belt and tentioner because that was broken and ratteling agenst the block, but no avail. luckly SOA is stepping to the plate and making it good to get my new LGT tomorrow .

piston slap under load?

Yeah, the more then boxer engines break in the more you will hear their awesome sound.......I'm not say'n that's what the problem is cuz it's virtually impossible to pick out what the problem is just from someone explaining a sound....

 

Is it only when you are actually in drive...so if you rev and hold at 2500 in park, can you hear the same sounds......? More details.....

The dual mass flywheel can make a rattle type noise. Mine does if it's very cold outside.

Yeah, the more then boxer engines break in the more you will hear their awesome sound.......I'm not say'n that's what the problem is cuz it's virtually impossible to pick out what the problem is just from someone explaining a sound....

 

Is it only when you are actually in drive...so if you rev and hold at 2500 in park, can you hear the same sounds......? More details.....

 

Scans,

In my baja I tried that and so did the dealier and it wouldn't replicate. Only in drive would it do it. They were thinking heat shields, and all of them are tight and not ratteling against anything. Then they looked at it 2 other times and got nothing but a scratching head. Finally they took the engine cover off and found that the timing belt was cracked beyond belief and the tentioner was broken and ratteling against the heads. So both were replaced under warranty and still the rattle noise is there.

 

Also, I would classify my noise more of a metel on metel buzzing noise instead of a rattle.

 

But after this evening, I won't have that problem anymore. The baja is going away and I will be saying hello to my new LGT after work. I can't wait.

 

Ben

For sure a heat shield problem. I use to get rocks stuck in my 2.5RS heat shields around the cat and exhaust all the time. They made quite a bit of noise and only in the 2500 to 3K range. Also, if any of the shields are barely touching the exhaust pipe or manifold, they buzz like all get out!

^^ Ahhh - I drive on dirt/gravel roads every day, so that makes sense. I'll clean out the shields and see if that takes care of it. Would also explain why both cars have the noise.

 

Thanks, bruddah.

Yeah, the more then boxer engines break in the more you will hear their awesome sound.......I'm not say'n that's what the problem is cuz it's virtually impossible to pick out what the problem is just from someone explaining a sound....

 

Is it only when you are actually in drive...so if you rev and hold at 2500 in park, can you hear the same sounds......? More details.....

 

"If I rev that high in park, then I can't hear it. If I'm in drive, then I can hear it (even if I'm sitting still with the brake on)."

Scans,

In my baja I tried that and so did the dealier and it wouldn't replicate. Only in drive would it do it. They were thinking heat shields, and all of them are tight and not ratteling against anything. Then they looked at it 2 other times and got nothing but a scratching head. Finally they took the engine cover off and found that the timing belt was cracked beyond belief and the tentioner was broken and ratteling against the heads. So both were replaced under warranty and still the rattle noise is there.

 

Also, I would classify my noise more of a metel on metel buzzing noise instead of a rattle.

 

But after this evening, I won't have that problem anymore. The baja is going away and I will be saying hello to my new LGT after work. I can't wait.

 

Ben

 

And how does that preclude that problem? Speaking from experience...

I had a similar noise with my 2003 legacy, in that case the sound went away when I pressed the clutch in. Probably some thing to do with the trow out bearing. But if this is happening with a automatic transmission then I dunno.