I have a '95 Subaru Legacy L Wagon AWD 5-speed manual shift. There a new noise that seems to be coming from the front half of the car. I can’t really describe the noise, but it only happens when all three conditions are met. If they are, the noise is continuous. 1.) The car has to be in gear–not neutral. But it doesn’t matter which gear. I tried revving the engine in neutral, but nothing happens. 2.) I have to be accelerating on the gas petal. If I let off the gas–even if the engine and vehicle speed haven’t yet dropped–there’s no noise. 3.) Engine speed needs to be at or above 2,000 RPM. It gets louder at higher engine speeds, but it’s pretty much proportional to the “normal” noises at higher speeds.
is this a rattling noise, a grinding, squealing…we need a little more help from you.
A rattling could be a exhaust heat shield loose and rattling, but it would be hard to find if it does not make the noise in neutral and revving. you might try grabbing the tail pipe when it’s cold and shaking up down and side to side. You wont hurt anything so be rough with it.
If it is a grinding it could be a wheel bearing grinding. Try going down a highway, with no traffic behind you and when you hear the noise take your foot off the gas and drop the shifter into neutral and coast for a bit. If the noise keep’s up it is a good chance it is a wheel bearing.
Squealing, it could be a bad drive belt. But again, this could not be diagnosed because you said it does not happen in neutral and revving it. You could check the drive belt for wear and cracking.
It’s somewhat similar to regular engine noise, but different. Nothing rattling, grinding, or squealing. It can’t be a wheel bearing, as only engine speed–not road speed produces the noise. Can’t be a belt either, as revving in neutral even with the A/C on doesn’t do it. It seems to be near the engine, and goes away instantly if I let off the gas petal. I don’t think a loose heat shield could respond that quickly.
One suggestion I’ve gotten elsewhere is it might have something to do with drive shaft. Any thoughts on that?
The description of the noise needs to be a little clearer as knowing this could help to narrow the possibilities down.
Are you saying this noise is only present when the engine is revved and the car is not in motion?
Does this come across as maybe a buzz or ringing? A whining maybe?
If you hold the clutch pedal down with the trans in gear and rev the engine is the noise still present?
Yosemite’s suggestion about a heat shield is a good one and should not be dismissed.
Sorry I can’t be anywhere near specific but the complaint is just too vague for me.
Most likely, the noise is simply the sound of a loose or broken heat shield on the exhaust system. Simply putting the car up on a lift for inspection should prove or disprove that possibility.
And–yes–heat shield noises do come and go almost instantaneously, as they tend to be sympathetic vibrations that are induced by a specific RPM range of the engine–especially when it is under load.
However, if you actually have a “gas petal” instead of a gas pedal, you could be hearing the sound of flower power.
Was the person who said it might be the drive shaft , someone who actually heard the noise. If yes, then maybe they heard the sound of a u-joint about to fail.
Do you ever hear a clicking sound as you start out from a stop. if yes then it could be the pin bearing being crushed from a dried out joint.
Another test would be to get up to speed of about 30mph and then back off the gas and quickly
go back to giving it gas…gas… coast, gas… coast, gas… coast , this will produce a clunking sound of a u-joint is sloppy.
many times a heat shield will only vibrate at a certain speed and I’ve seen ones that only vibrate at a certain RPM speed…when the engine is vibrating at the right rate.
We REALLY need a little better description of “The Noise” I mean…look at what we have to go on here… Very little to nothing describing the noise.
Get creative…Does it sound like a Cat Meowing? An Elephants Trumpet? A Squeak…a Squeal? A rattle? A hum? A rumble? SOMETHING…
I see you describe it as Akin to Regular Engine Noise…if that is the case how do you know its not just normal engine noise? A Heat shield would be in the RATTLE category for sure.
It could be a Transmission Gear whine… Have you checked the Transmission Gear Oil level? It can be checked…and if it is low or out of lube…it is Tearing itself apart inside…and would correspond to regular engine noise…only exaggerated.
Check THAT LUBE LEVEL IN THE TRANNY…IT IS MORE THAN IMPORTANT Sir. Let us know what you get