After driving approx 4 miles this evening I arrived home and was having a nosey under the bonnet of my new (to me) p38 2.5DT

I removed the EAS cover and noticed the compressor was quite hot, could touch it, but if it had been any hotter it would've been uncomfortable.

Is this normal?

Thanks

Pete

Yes, its normal. On a hot day its normal for it to get even hotter and become too hot to touch. It wont self destruct or anything, if it does overheat for any reason its got a thermal cutout sensor thingymabobo in it which tells the EAS ECU to stop running it.

-Wills

Hi Wills,

You are indeed a valuable forum member, your advice has been invaluble to a novice such as I! Just a few more "simple" questions: I have just replaced my "drive pack", which (thanks to advice from the forum), seems to have fixed my "fault" problem. I (for the first time, I think), can hear the compressor working! It pumps for a few minutes and then shuts off, sometimes if stationary, as soon as I release the brake pedal to drive off - it stops. I am not sure if hearing the "pump" now is due to the "drive pack" replacement, or to the rubber mounts on the compressor, being disturbed when the "drive pack" was replaced? I have tightened the mounts and they seem OK.
I do not seem to have a leak in the EAS system, as the car does not "drop" if I leave it standing with a door open. It responds instantly to "raise or lower" commands. However, if there is no leak, why does the compressor keep pumping? If there is no leak, why does it have to replace "lost" air? It's got me beat - over to you!

Cheers, Tonys

I'm taking a stab in the dark at this one but it could be when you lower the system it vents the air out into the atmosphere instead of putting it back into the system, therefore it needs to recharge,

ever been on a bus? heard a loud hiss when driving along side one? that's the pressure relief valve letting off when the air in the air brakes reaches a certain pressure, of course it needs to build up again, and every press and release of brake pedal vents air off, my guess is there is also a pressure release valve somewhere in the system and as the EAS on a RR is no where near that of a bus your not hearing it vent off when it reaches a certain pressure or when you lower the suspension (like i said, this was just a stab in the dark so dont take my word for it....

TWEETS,

Thank you for that, sounds logical? If that is the case, I will not worry so much when the compressor keeps on pumping!

Regards, Tonys

Tonys said:

I (for the first time, I think), can hear the compressor working! It pumps for a few minutes and then shuts off, sometimes if stationary, as soon as I release the brake pedal to drive off - it stops. I am not sure if hearing the "pump" now is due to the "drive pack" replacement, or to the rubber mounts on the compressor, being disturbed when the "drive pack" was replaced? I have tightened the mounts and they seem OK.

However, if there is no leak, why does the compressor keep pumping? If there is no leak, why does it have to replace "lost" air? It's got me beat - over to you!

Click to expand...

The reason you are hearing the pump is because you have tightened the nyloc nuts for the compressor too much and are crushing the little rubber mounts which the compressor has. The nyloc nuts need to be tightened to around 1.5nm to 2.0nm. This doesnt sound like its very tight but thats why you have the nyloc nuts, so they dont come undone. Loosen off the nuts a little and then try sitting in the vehicle again and see if you can hear the pump then.

You dont say exactly when the compressor keeps pumping. If you have a door open and then check out the compressor is it reguarly cycling then?? If so you may have a leak, if it isnt then you are pretty ok with the fact you dont have a leak in the tank or in the line to it.

Its normal for it to cycle on and off when driving as the suspension system makes constant adjustments to keep the vehicle level.

How often is it cycling on and off?? You may have a slightly leaky bag or a valve block that could do with an o-ring kit.

-Wills

Any compressor will run hot, it's normal. Compressing air or gases generates heat.

wills said:

The reason you are hearing the pump is because you have tightened the nyloc nuts for the compressor too much and are crushing the little rubber mounts which the compressor has. The nyloc nuts need to be tightened to around 1.5nm to 2.0nm. This doesnt sound like its very tight but thats why you have the nyloc nuts, so they dont come undone. Loosen off the nuts a little and then try sitting in the vehicle again and see if you can hear the pump then.

You dont say exactly when the compressor keeps pumping. If you have a door open and then check out the compressor is it reguarly cycling then?? If so you may have a leak, if it isnt then you are pretty ok with the fact you dont have a leak in the tank or in the line to it.

Its normal for it to cycle on and off when driving as the suspension system makes constant adjustments to keep the vehicle level.

How often is it cycling on and off?? You may have a slightly leaky bag or a valve block that could do with an o-ring kit.

-Wills

Click to expand...

Thanks Wills,

Have loosend off the Nyloc nuts and it is quieter. I think I will replace the rubber mounts, I am sure this will help even more?
It does not run all that often, mainly first trip in the day. Interesting enough, the compresser will cut out quite often as I release the foot brake to move off.

Thanks again for your help. Tonys.