My air compressor seems to be running too long or maybe all the time, is it worth changing the relay as I have read that they can stick. Otherwise it maybe a leak but I can't see one by the level of the car or hear one?? Any ideas or suggestions appreciated.

yes, change the relay is one of the first. I now add it into the yearly schedule so I dont have to worry about it. It's less than a tenner and takes 2 minutes. Bodsys Brake Bible
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Does changing the relay help with any other issues e.g. sagging suspension or a slow lift when asking for off road height? 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

It'll only help sagging suspension if the relay comes with 50m or 3T steel wire to brace it alll up....

Seriously though, it wont help with sagging and it's not likely to help with slow lifting.

Slow lifting is usually caused by it getting too hot or just not being able to get the pressure in quick enough. Bodsys Brake Bible
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Thanks Bodsy, upon further inspection it is shutting off, I have a relay coming so will change it anyway. I think the problem is that the compressor is noisier that it used to be, what would that indicate and should I do anything at this stage. Many thanks..

Thanks Bodsy - I guess that question deserved a slightly -taking reply  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Rrs

1JBS - did you know that's the number plate that I've wanted for a very long time.....

Anyway... Louder compressor could be a broken mount. Has anyone jacked the car up recently? They may have jacked on the compressor cover.....
Sometimes they do get loud before they fail. Don't know why TBH but they do.
Usual failure is the dryer unit no longer being able to dry or the carbon ring on the piston wearing out.

You can get a service kit which may help, but is likely to only put off the inevitable.... Bodsys Brake Bible
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RRS Timed Heat/Remote kits - Contact me
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Clock On The Dash/ SNOTM /3Flash / BT Update /Service Reset/Error Codes read\ Gearbox Reset
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Yes I was lucky to be able to buy the number plate many years ago before the values went really high!
Thanks for the info I think it is probably just wearing out and getting a little noisier. No one has jacked it up incorrectly.
I made that mistake once on a friends 05 disco helping them out with a flat tyre, cost £800.00 I will never make that mistake again!