Hot p38 suspenion air compressor

[donp38]

Hi Guys.

I have replaced the air bags (as theyt where the original and perished) and just replaced the air compressor.

The air compressor is getting really really hot after say 10 miles/ 20mins work. Can anyone advise its 'typical' operation temperature?.

I cannot find any faults and the car stands firm and square after not running over night, so can't see any leaks.

Could the compressor be faulty?

thanks.

 

[wammers]

Your compressor should not be running for 10 miles or indeed 20 minutes. If there are no leaks it should run intermittently only. When it reaches 120 degrees it will cut out to cool down. Once the suspension is up compressor should only run now and again. If it is running all the time you will have a leak from pressure storage side of system. This will not make suspension drop.

 

[donp38]

Many thanks. All understood. I'll have a look for leaks tomorrow and let you know.
I now have a good idea where the problem could be.

So typically, so no more than 55deg C? I'll get my temp sensor on it.

 

[Datatek]

Book say's max operating temperature is 120C, however as Wammers said it should only run intermittantly and not reach that temperature unless all the air pressure has gone from the system.
Take the exhaust filter off the valve block and see if there is air escaping which would indicate diaphragm failure. Otherwise it could be the compressor.

 

[donp38]

Not done anything yet. However took it 2miles down the road with the bikes on.
On returning to the car it wouldn't start. I bridged it at the solenoid to get it started and get us home. I have checked the fuses and the 40amp MF2fuse is blown.
Do you think this could be related to the hot compressor?
If so, what do you recon my sequence of fault finding should be?
I will get back to the car with replacement fuse on Thursday.

 

[Saint.V8]

Looking at the Circuit Diagram...(Attached below) MF2 is 30A and is for the starting circuit and the Air Compressor relay so it is possible the overstressed Compressor could be at fault...but to draw 40A is one heck of a lot, me thinks the compressor is totally shot and shorted inside....

When you go back I would advise removing the Air Comp relay, and pull the multiplug to the Compresser....it will cause EAS Fault, but better that than risk a electrical overload fire should the fuse be slow to blow or short completly....

 

[donp38]

the plot thickens.

I have gone and had a look and the MF2 and MF3 fuses are 40 and 30amp repectivley!
you are quite right, MF2 should be 30amp and MF3 should be 40 amp!
So I now suspect that there has been an issue before I bought the car with MF2? Any ideas?

Many thanks for the logic saint. Do you still suggest this? I will get a replacement air compressor sorted for Thursday also.

 

[Saint.V8]

What year is your P38...looks like the MF2 fuse serves different circuits depnding on year....

 

[donp38]

It was built dec 1995, registered jan 1996.

 

[Saint.V8]

Thats OK.....the diagram I posted is correct then....

In 1999 it changed to a 50A fuse, to run the Secondary Air Injection Pump....

So I would imagine, if you are having problems with the Air Comp that could be the issue....

It wouldn't hurt just to check all the connections for the Starter system also, just to be sure....

 

[donp38]

many thanks.

I will have a good look around on Thursday and go with your logic.

I will also change the two fuses around so that MF2 and MF3 have the correct sizes.

As you can see in my previous note, MF2 blew with a 40A fuse not the correct 30A!

 

[Saint.V8]

This is why I would exercise caution and if you are going anywhere in it, to disconnect the Air Comp relay and Multiplug, until you can sort the pump (if this is indeed the issue) as to blow a 40A fuse, something is clearly amiss.

Best of Luck my friend, let us all know how it goes.

 

[wammers]

Strong chance the rear bearing carrier has broken and is letting bearing and armature flop around like a whippets dick.

 

[fanatic]

Strong chance the rear bearing carrier has broken and is letting bearing and armature flop around like a whippets dick.

Snigger very informative and we now have a self professed whippet dick specialist

 

[wammers]

Snigger very informative and we now have a self professed whippet dick specialist

Thank you kind sir. Just an old saying i heard, know nothing about whippets dicks really. Honest. Rear bearing carrier breaks letting armature wobble about hitting stator. Net result. Heat.

 

[donp38]

Hi Chaps.

Many thanks for helping on this one.

Inspected the wiring and replaced compressor today. Checked and put back the soleniod.

Started it up and all is well.
Only ran for 1/2 hr but all seams well. This new replacement is running much cooler than the 1st 1st new one. Checked and checked to ensure compressor switched off and on as it should. All looks to be well.

Gentlemen, again, many thanks.