Rear Compressor runs all the time

Hi there,

I've got a 1999 V reg disco TD5 - 7 seater. In the past few days I've noticed that there is a noise coming from both sides of the rear axle that sounds like an air compressor running. When the ignition is on (but engine not started) the sound runs for a minute or two then stops. But as soon as the engine is started the sound comes back and runs continuously.

I thought that maybe its a leak in the air suspension, but the suspension doesn't show any sign of going down overnight, plus I'm baffled as to why it seems to get to the right pressure and switch off when the electrics are on, but as soon as the engine is running it doesn't switch off.

Any ideas??

Thanks

Wrong place for the suspension compressor?

Could it be your fuel pump?

That runs up to pressure then stops, but needs to run constantly when the engine is running.

MW

Its quite a loud noise - you can hear it inside with all the doors & windows shut. Would a fuel pump make such a loud noise?

yes

Thanks - I've just had a look at the fuel pump posts and this could be the problem. Is it more likely to be the pump filter or the fuel filter?