I’ve had a 2004 Disco for a couple months and still trying to fix some remaining issues. There is a noise that kind of sounds like an exhaust leak but I haven’t been able to find any using the shop vac/soap test. It is much more noticeable when the engine is cold and I only hear it when I’m giving it gas. It quiets down when the engine is warm after driving for a while.

I tried to take a video of it and you can for sure hear it at the beginning and end of this. It’s windy for the middle few seconds of the video that’s my bad.

https://youtube.com/shorts/xWEfIFoNmyk?si=10Tke6eHso5W5qys

 

You could have a cracked cat or pipe. Do the shop vac test again and cover more area.

 

Have you checked the SAI pipes on the side of the heads? I had a tiny crack in one that caused a similar issue.

 

Your Discovery has decided it wants to be a diesel.

 

I believe this might be coming from my transmission? It increases when I’m giving it gas and I can’t hear it when I’m coasting or idling.

here is a video you can hear it louder when I get close to it.

 

Old thread, but did you ever get this sorted?

 

I have this same problem on my 04, however it’s not really a problem. It’s related to operation of the SAI valves and exhaust noise being amplified when cold. Sometimes it’s inexplicably louder than others, but it always quiets down eventually. Not sure if it’s a symptom or a cause, but it’s done it for quite a while. It sounds similar to what’s being described here.

Redrover I believe this is different to what you were experiencing so I didn’t reply in that thread.

 

I have nothing substantive to add to this thread, but everyday I see the title and this comes to mind: