What's this sound?

[rturbo 930]

My e30 started making this sound not too long ago. I have a pretty good guess what it is, but I want someone to confirm my thoughts. It starts around ~2500rpm, and it's most noticeable when kind of feathering the throttle. Doesn't make the sound (at least not noticeably) hard on the gas, or completely off the gas. It'll do it hot or cold.

I should add, it idles really rough when started cold. It always has, but it's a lot worse now than when I first bought it. It also burns and/or leaks a lot of oil.

Here's a video. You can hear it around 2 seconds in, and it fades out around 7, until I get back on the gas again at 10s in.

[E30_Pare]

Doesnt sound very happy. Hows your power? Any noticeable loss?

[rturbo 930]

Doesnt sound very happy. Hows your power? Any noticeable loss?

I wanna say it's lost a little upper rpm power, but I'm really not sure. I don't redline it that often. When I got it, it had a rough idle, but seemed to pull fine from just off idle to redline. But this is the only E30 I've driven so I've got nothing to compare it to. I haven't noticed a difference in power under 4k rpm.

[E30_Pare]

I have a feeling its something to do with your exhaust system. Perhaps its rotten out

[rturbo 930]

My muffler has a small hole in it that I've been meaning to fix, but otherwise it's solid. And it definitely sounds like it's coming from the engine.

[AndrewBird]

Exhaust leak was my first though, but it could also be alternator or water pump bushing going out or internal engine problems, though the later seems unlikely if it isn't down on power or anything. Maybe the mechanical fan clutch?

Try taking the accessory belts off one at a time and see if the noise goes away.

[TurboJake]

Could be the exhaust heat shield too. Very typical of them to rattle against the body or exhaust at only certain RPM and throttle positions/load.

IF it's the exhaust heat shield, 9 times out of 10 you can recreate it while not driving. It's also pretty obvious (Sagging, easy to move, etc)

[tino225]

2 things check your idle speed, check the wiring meanwhile clean your throttle body second check your headers u might have a leak from the gasket e30s r old.