P38A Compressor not running, what to check?

300bhp/ton · Jul 24, 2018

So, had some issues with my p38 a few weeks back. Just got to having a look at it.

The back was dropping and I could hear a hiss. But couldn’t tell from where, sounded in the middle more than one side.

On the way home there was a loud sound of rapid decompression. The suspension stayed up. On arriving home and lowering to access height it rapidly sank to the bump stops and hasn’t raised since.

On the same journey the exhaust did develop a blow. I’ve traced this to a hole in the rear of the middle silencer at the top. Slightly pointing towards the rear passenger airbag.

I have not yet found the cause of the air leak.

However running the Vehcile the compressor does not appear running. Having crawled under and listened and felt for it vibrating.

Is there anyway to easily check the compressor by other means?

My Nanocom is not reporting any fault codes and seems to think the compressor is running.

Anyone any ideas where to check next? I don’t want to blindly buy a new compressor without being certain it needs replacing. And I need the compressor working to try and find the air leak.

Had all doors closed when checking the compressor. The ‘Door/disable’ was set to Closed.

kurtjohnson10 · Jul 24, 2018

I have a new compressor availible mate if you cant repair your other one.

Saint.V8 · Jul 24, 2018

Why be under the car to listen to the compressor?

The ECU pulls in the compressor relay. It will report that the compressor is on as it has told the relay to switch.....it will not know if the pump is actually running. Check the relay, the fuse and the thermal cutout.

300bhp/ton · Jul 24, 2018

Saint.V8 said:
Why be under the car to listen to the compressor?

Was under looking for the exhaust blow and any signs of the air leak. Was no bother to double check. The exhaust is also so loud with the leak you’d not hear the compressor from the drivers seat or standing next to the vehicle.

Saint.V8 said:
The ECU pulls in the compressor relay. It will report that the compressor is on as it has told the relay to switch.....it will not know if the pump is actually running. Check the relay, the fuse and the thermal cutout.

Thanks. Do you have any detailed info on how to check these things? Nanocom is saying the thermal switch is normal.

pete12345 · Jul 24, 2018

There’s a how to on here from warmers I think going rite through the procedure

brianp38dse · Jul 25, 2018

in the Tech archive top left of range rover home page.

ovalandrover · Jul 25, 2018

on your nanacom there is in the outputs a method of turning on and off the compressor to see if its running .

Datatek · Jul 25, 2018

"On the same journey the exhaust did develop a blow. I’ve traced this to a hole in the rear of the middle silencer at the top. Slightly pointing towards the rear passenger airbag.

I have not yet found the cause of the air leak."
Exhaust blow may well have melted a pipe.

"However running the Vehicle the compressor does not appear running. Having crawled under and listened and felt for it vibrating."
Crawled under & listened? where do you think the compressor is?
The compressor is in the black box above the nearside inner wing behind the air filter. as others have said, the compressor can be turned on and off with diagnostics. First place to check is the fuses.
The compressor is not designed for continuous running, so feeding your air leak may knackered it.

saxavordian · Jul 25, 2018

Would a simple soapy liquid test on the air bags and pipes not discount these problems first. The compressor if working overtime could mean the seal for the pump is warn out. If my memory serves me and watching to many Wheeler Dealers Ed came across this issue of the pump in the end needing replacing as the Seal was unreplacable.

Datatek · Jul 25, 2018

saxavordian said:
Would a simple soapy liquid test on the air bags and pipes not discount these problems first. The compressor if working overtime could mean the seal for the pump is warn out. If my memory serves me and watching to many Wheeler Dealers Ed came across this issue of the pump in the end needing replacing as the Seal was unreplacable.

That Wheeler dealers was a joke. The seal is always replaceable, Ed didn't even try, nor did he check why the pump had failed.
As well as replacing the piston seal, the cylinder can also be replaced.

Grrrrrr · Jul 25, 2018

The thermal switch is in the top of the EAS pump. As ovalandrover says, you can force the pump on using the Nanocom and this will override the thermal switch but as Datatek says, you've almost certainly melted an airline or the bag itself - more like the airline. You can splice in some airline with appropriate connectors. Or I can post you a few inches of line - or drop in if you like and you're in Aylesbury.

wammers · Jul 25, 2018

Datatek said:
That Wheeler dealers was a joke. The seal is always replaceable, Ed didn't even try, nor did he check why the pump had failed.
As well as replacing the piston seal, the cylinder can also be replaced.

Wheeler dealers is always a joke. The bit about make sure you get the correct parts then fitting the wrong replacement headlamp was a classic.

saxavordian · Jul 25, 2018

wammers said:
Wheeler dealers is always a joke. The bit about make sure you get the correct parts then fitting the wrong replacement headlamp was a classic.

Yeah when they abused Landies my heart sinks when the poor sod who buys it for a pig in a poke. Good Landies should remain the same and driven that way.

pwood999 · Jul 25, 2018

The clue is in the original post.

300bhp/ton said:
On the way home there was a loud sound of rapid decompression. The suspension stayed up.

If the suspension stayed up on the way home, surely the airlines feeding the bags must be ok ? (assuming the journey was more than a few minutes) Sudden loud sound of air escaping was probably the pipe from compressor to valve block blowing, or could be the exhaust silencer popping out ?

Do the usual manual checks in the Tech Archive, and then report back.

Grrrrrr · Jul 25, 2018

pwood999 said:
The clue is in the original post.

If the suspension stayed up on the way home, surely the airlines feeding the bags must be ok ? (assuming the journey was more than a few minutes) Sudden loud sound of air escaping was probably the pipe from compressor to valve block blowing, or could be the exhaust silencer popping out ?

Do the usual manual checks in the Tech Archive, and then report back.

Seemed to be a bit contradictory to me?

300bhp/ton said:
The back was dropping and I could hear a hiss. But couldn’t tell from where, sounded in the middle more than one side.

On the way home there was a loud sound of rapid decompression. The suspension stayed up. On arriving home and lowering to access height it rapidly sank to the bump stops and hasn’t raised since.

So the back was dropping but the suspension stayed up?

Datatek · Jul 25, 2018

pwood999 said:
The clue is in the original post.

If the suspension stayed up on the way home, surely the airlines feeding the bags must be ok ? (assuming the journey was more than a few minutes) Sudden loud sound of air escaping was probably the pipe from compressor to valve block blowing, or could be the exhaust silencer popping out ?

Do the usual manual checks in the Tech Archive, and then report back.

Exhaust blow, pipe to air tank is most likely.

P38A Compressor not running, what to check?

300bhp/ton

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kurtjohnson10

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Saint.V8

Dyed-in-the-wool 100% RR Junkie

300bhp/ton

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pete12345

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brianp38dse

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ovalandrover

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Datatek

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saxavordian

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Datatek

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Grrrrrr

Technician, Bodgit & Scarper Ltd

wammers

No longer with us, RIP

saxavordian

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pwood999

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Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

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