Yeah I know a noise thread but worth a shot , basically I can hear a noise almost like running on 3 cylinders like a thrumming noise its really apparent at 2500-3500rpm, car doesn't feel down on power. It seems to be either coming from the back of the engine or in the middle underneath?

Afr is spot on according to wideband which would show up a leak.

I know its hard to diagnose, any ideas? Its definitely not the exhaust.

Cheers

 

Might be worth trying to do a video and uploading it here or having a look around on YouTube to see if you can diagnose it?

Does it only do it under load when driving or does it do it if you have the bonnet up when stationary and rev the engine?

 

Its only under load, not when revving engine. Seems like its now coming from the back what does a knackered diff sound like?

I'm limited to what i can do but tried rotating the prop shaft when the car was sat with the handbrake on, there is a little play from the propshaft but no leaking.

 

Here is a video, it sounds worse than it is. Unfortunately i thought i took a better video, but must have pressed the stop button

Kind of sounds like a subaru exhaust.

http://imageshack.us/clip/my-videos/717/mg1.mp4/

 

Sounds like a tractor.

 

I know! its more apparent at lower rev's, if i let off the accelerator it doesnt make a noise.

And thinking about it a knackered diff would sound different and give me bigger problems, plus the car seems to accelerate fine.

What about the propshaft?

Maybe the exhaust packing?

I'm sure its coming from the rear.

 

That might well be your diff on its last legs unfortunately AJ...it wouldn't surprise me if you give it too much welly that it'll let go altogether if it is, sounding as bad as that. Look/listen to these YouTube videos...sounds identical to me. The only difference with these below is the sound is throughout the rev range but from what I know they'll start at certain revs and then gradually get louderlouder ore linear in noise across the rev range until you finally lose drive to the wheels.

http://www.youtube.com/watch?v=M2C_g...e_gdata_player

http://www.youtube.com/watch?v=ZOXIJ...e_gdata_player

http://www.youtube.com/watch?v=7nzOP...e_gdata_player

 

It sounds like airbox off, like a deep thrum. I've had a diff go on another car and it was a whine and then bang.

It could be something internal in the exhaust i guess. What does it sound like sat still when you blip it?

 

No noise mate when idling, I've had it on a lift today and it appears to be coming from the diff but not a metallic grinding noise.

thanks

 

It's MB pre recorded mating call - he's rutting for you AJ