I have a throaty exhaust like sound on my 2002 Discovery which is bugging me. I am not very mechanical and in Laos where getting to a good mechanic, or one that has even seen a Discovery, is a bit more challenging.

When the car idles, there is no sound. After a cold engine start the sound is hard to hear. As the engine gets to temperature, the sound is much more noticeable. Under heavy engine load (going up steep Laos hills) the sound is much more noticeable. When going down hill, even engine braking, you can't hear it. With the window down very easy to hear, with the window up a little harder (just to give a sense of how loud it is).

The sound is hard to describe. Best I can say is it throaty, but not not a deep rumbling throaty. Noise sounds like it is coming from the drivers side engine bay. But have not got a good location as there is no noise when at idle.

So, I took a look under the car at the exhaust system this morning. And I see that where the drivers side exhaust manifold connects to the rest of the exhaust system, there is a nut and bolt missing from the joint, see attached photo. Before I put a new/replacement nut/bolt here, I wanted to make sure that it is not meant to be missing, as it seems strange that it would be missing or would have fell off. Can anyone confirm if I should go ahead with new bolt/nut?

Sorry for just a lame question, but do not want to make things worse. Thanks in advance.

 

Nope there should be a stud and a nut. Stud is in the exhaust manifold. What might have happened was the previous owner busted the stud and never replaced it. Below are the parts you will need. I would go ahead and replace the gasket and the other studs.

STUD EXHAUST MANIFOLD V8, RNE742, LR009704 - Rovers North - Classic Land Rover Parts

NUT M8 Y PIPE-EXH MANIFOLD V-8 3.5/3.9.., RNE903, WYH500060 - Rovers North - Classic Land Rover Parts

PRO LINE GASKET MAN/EXH V-8, PLE888, ETC4524 - Rovers North - Classic Land Rover Parts

 

Missing the same stud on the right manifold. Not a peep out of it. Don't know why.

 

I would not touch it.
That joint to the manifold is working.
Just a little noise is fine.
If you touch any of those bolts to get the joint apart to remove the stud,
you'll snap all the studs.
Probably.

Been there and done this.

http://jeffreyfall.com/landrover

 

Thanks. Given the noise is not too bad, and I am going with jfall and the "don't touch it approach" (for the moment). Thanks ralphobell for the links, when I am back in the states in 6 months I will probably do the fix, as it will be a good learning experience for me.

 

I did fix it. Needed new cats and y pipe. Thank you PO whoever you are for the hack weld job. It leaked horribly from that area. Turned out they stripped the studs on both manifolds. Didn't find out until I was ready to reinstall the new magna flow cats. Ya me. So yea.. If you can tolerate it.. liver alone.