Rattle In the Engine Bay

[JD_MS3]

As the title says. Here's the scenario... I pulled into my garage after coming back from the store (It was about a 15 min drive on the freeway, averaging 70mph) I dont have a turbo timer, so I let the car run while I bring the groceries into the house, and on my way in I heard a rattle/knock coming from my car, so I pop the hood to see if I can find it, and to me it sounds internal. The only Mods I have down to the MS3 are an Ingen CAI and Throttle body spacer, and I checked all the hardware to see if everything was in tacked.

I also tried recording the sound but its to faint when I play it back, cuz the injectors, fan, and exhaust over power it on camera.

My thoughts come out to it being engine knock, or maybe worn gears in the transmission. I dont drive the car much in the first place because my daily driver is my P5. and the MS3 only had 25,000 miles on it.

My wife also drives the MS3 on occasion, and she has stalled it a couple of times.

Basically Im just looking for opinions, before I take it into the shop and just wanting to know if it will be covered through warranty. This is my second turbo'd car, and before this I never experience a Bad turbo, so I wouldnt know what it sounds like. I do have Prosport Boost gauge, but its not installed. But Im leaning towards it being an engine knock. Or maybe my rear engine mount finally had its day and the engine vibe is causing it to rattle?

If some people can help i would appreciate it.
-Thanks for reading.

 

[JD_MS3]

I restarted the car to narrow down where its coming from and you can here it most at idle around. It comes from the driver side. Around the shift linkages and transmission. Most noticeable around the bellhousing.

 

[MSMS3]

Do you know the normal sound of the clutch throw out bearing? It is typically only noticable when at idle with the clutch out and tranny in neutral. It does sound like a distant rattle.

Does sound go away when you depress the clutch? Just guessing at this point.

 

[JD_MS3]

i guess that would be it, because after 5-10mins its stops anyways, im not concerned about it anymore.

 

[liquidflem]

the clutch throw bearing is pretty loud in this car - i bet that's it.

 

[TheDoc]

As was said above it is not uncommon for the throwout bearing to be making some very horrible-sounding noises.

 

[MSMS3]

My thinking was throw out bearing, but my only reservation is that it is unclear whether OP's "rattle" stops when he pushes the clutch pedal down. Throw out bearing noise should disappear when you push down the pedal.

 

[Darth Vader]

I get a rattle when I hit a sleeping policeman just right. It is, as far as I can tell, the transmission shift shaft/linkage bouncing up and down in it's pocket on the top of the trans. I haven't really chased it hard though, because it's hard to duplicate without rolling.

Rattles from that area can be caused by the former airbox bracket being broken, usually because of a Cobb SRI install. Two little spot weld hold it on and they snap off and the bracket rattles. Grab the exposed end, sticking out of the front of the underside of the batt box and give it a healthy tug. If it moves at all, that might be the problem.

It won't be engine knock, if by which you mean pre-ignition, as there's no load. If you mean a rod or main bearing knock, they have distinctive sounds. A rod big end or main bearing knock will be a deep clock-clock kind of sound, at relatively low frequency. The small end rod knock will be similar but, higher pitched. Valvetrain clatter is very high frequency and high pitched ticking/tacking sounds. Some of that noise is normal, coming from injectors and the solid valvetrain on these cars but, if it's really loud underhood, no good.

It's very difficult to inform the initiated as to what is an ok sound and what isn't. You really need practise and experience to tell these things.

 

[Hyun]

Could be belt tensioner and tensioner pulley. You might not hear all the time now but as time goes on, it gets more frequent. Better take it to the dealership before 36k warranty runs out.

 

[noobinacan]

I started getting the rattle sound from the engine bay as well..
constant through all RPM range..
I did not get the sound on my drive back...but it comes and goes.

and its not 36k,..its 60k cause its drivetrain warranty.