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Discussion Starter · #1 ·
There was a recent thread regarding this topic, but there was no firm conclusion as to the cause. Has anyone successfully resolved this situation or determined a definite cause?

My car makes a brief chirping noise when decelerating (usually in 3rd or 4th around 2000-3000 rpm). It does it when warmed-up too. No noise when accelerating. It doesn't do it every time I decelerate either. I did hours of driving yesterday and it seemed to be on a roll. When in the car, it seems to be coming from the engine.

My car is modified -- turbo back exhaust, ebc (done 3 weeks after buying the car), and recently an uppipe and unorthodox pulley last week at 1200 miles (all work is done at the dealership in Irvine, CA). The noise seems to be made more often now. Mods don't seem to be a factor in whether it chirps or not. I've read posts from other owners who report the same problem and are completely stock.

The fact that it "chirps" at a certain rpm, and does so inconsistently, makes me think that something is vibrating sympathetically when the right frequency is hit upon deceleration. The engine vibrates differently at this time, and perhaps this is why it only happen then.

Oh yeah, one other noise -- again, upon deceleration, at about 2000 rpm, I hear a brief very light "grinding-like" noise in the transmission. I realize this might be completely normal and know that these cars do make noise, especially when modified. I've been very good to the transmission so far, so it's not due to abuse. It's made the noise since day 1 and hasn't changed. I've read about transmission issues with early VIN & engine #'s, but my numbers are recent, and I believe the issues were resolved or at least improved. I haven't put synthetic oil in the transmission yet, so maybe this will help. I only have 1400 miles, and don't want to do it prematurely.

(Side note: The service manager at my dealership said never put synethic oil in the engine (he didn't say anything about the transmission). He said at about 20K miles, they start to burn oil, and that he hasn't had this problem with cars using regular oil. He said to use Castrol and change it every 3,000 miles).

I don't mind noises as long as they're "normal" and do not indicate a potential problem. I'll call the dealership tomorrow and see what they say.
 

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Changing to synthetic before the engine has completely broken in can cause it to consume oil later in life. I recommend waiting until 10-12k miles before switching to synthetic. I have well over 20k miles and my car consumes not a drop of oil.

-Jim
 

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Discussion Starter · #4 ·
Yes, he said to not use synthetic.

I've always used synthetic in my other cars and was disappointed to hear this. Apparently PlatinumWRX hasn't had any problems when switching to synthetic after the engine has broken in, so I don't see why I can't do the same.

This next weekend, I think I'll switch to synthetic transmission oil, however.
 

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Sure it's not the infamous exhaust hanger chirp from the rear of the car? I had to have a friend rev my car in neutral while I climbed around under the vehicle like a cockroach to find the chirp from my rear/muffler exhaust hangers. :)
 

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Discussion Starter · #6 ·
Exhaust hangers? Hmmmm... I'll check on that.

The sound seems to be centered right in front of my dash. Today, I actually wondered if it wasn't the shifter or transmission. It's such a light sound that I would be surprised if it makes it from the engine to the cabin so clearly.
 

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yeah my Subaru mechanic said the same thing...if you switch to synthetic BEFORE 15K or so miles (or push the motor past 4K rpm for the first 4500 miles) the motor doesn't break in properly and will burn oil since synthetic reduces wear so much the motor can't break in with it.

he said don't change tranny or diff oil till 30K as well or you get similar wear problems there.

exhaust hangers, loos hardware on the exhaust or loose heat shielding sounds like the chirping culprit.
 
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