e46 Aircon System (M54 motor)

[Chicayne]

Hey all

When engaging the aircon, and there is no gas in the system, is the aircon compressor supposed to spin or not? Or is the compressor perhaps pressure sensitive (i.e. it will not engage if the system has no gas, and therefore no pressure)?

Reason: I just had my system emptied as I has to replace a valve in the system. Machi says everything is fine but when I engage the system there is no drop is revs (to indicate engagement) nor does the compressor spin. He says I need to regas it first, but I would not want to regas without being (as close to as) 100% sure that I won't be wasting a regas.

Thanks in advance.

 

[Nella11]

If there's no pressure the pump will not engage.
There's a pressure switch normally by the receiver dryer that cuts the power to the compressor

 

[Chicayne]

Thanks Nella11. And sorry, meant to say pressure switch, not valve.

Its exactly that switch that I replaced.

So all seems a go for now, will regas and see what happens.

 

[kilotango]

If there's no pressure the pump will not engage.
There's a pressure switch normally by the receiver dryer that cuts the power to the compressor

:withStu:

correct, the compressor wont engage without pressure... the pulley will just turn and do nothing

 

[Spiro]

yep all valid points above...



no gas, will not allow the pump to engage...




.

 

[Chicayne]

Ok...so after having replaced the pressure switch and regassing the correct way...its now...


STILL NOT WORKING!! :argh::argh:

Compressor doesn't engage, revs don't drop, pulley doesn't spin...nada!!

However, and this is the strange truth, while I'm driving, at a speed of at least 100km/hr for a minimum of 15secs, the aircon now kicks through yummy cold air. But stops as soon as I drop speed below 100kms/hr...:wtf::wtf:

 

[Waseem 333i]

Im just taking a guess here. Possibly the fan is not working. Maybe the car knows its traveling at speed and has no need for the fan so it kicks in the compressor. Check if its plugged in nicely and maybe fiddle around with the wiring to see if if comes on. You could also go to a spares shop or something and plug in a new fan just to see if it does anything

 

[Spiro]

from my understanding,


when you for example take off in 1st, there is a relay behind the glovebox, that will kick the ac from running mode to stopped, once the displacement request is eased up, it allows the pump to re-engage


best bet on this, if the relay is not working there should be a possible error code, best to INPA the car and check it out...


which area are you in ?

 

[Chicayne]

from my understanding,


when you for example take off in 1st, there is a relay behind the glovebox, that will kick the ac from running mode to stopped, once the displacement request is eased up, it allows the pump to re-engage


best bet on this, if the relay is not working there should be a possible error code, best to INPA the car and check it out...


which area are you in ?

She's currently resting in Rondebosch, Cape Town. As per the machi, diagnostic does not indicate any issue, which to me is a concern all on its own. I'm almost dead sure he would have checked the fan. Either way, will then have to perhaps take it to a specialist to see if they can test the entire system and perhaps then identify the issue.

 

[Cape_Tonian]

There's a guy in Kenwyn that does aircon repairs, diagnostics and just about everything ac concerned.

He completely reconditioned my ac compressor and had another ac also sorted by him.

I can forward you his digits if you're interested to go see him.

 

[Bazza]

I have an E46 with M54 motor; I noticed you said that your revs used to drop when the a/c is engaged, mine doesn't drop revs at all when I engage it. Maybe there is another issue there.

 

[kilotango]

She's currently resting in Rondebosch, Cape Town. As per the machi, diagnostic does not indicate any issue, which to me is a concern all on its own. I'm almost dead sure he would have checked the fan. Either way, will then have to perhaps take it to a specialist to see if they can test the entire system and perhaps then identify the issue.
[/quote]

not sure about the manuals, but fastest way to check the fan operation on an auto is to start the car, turn on the AC then check if the Aux fan turns on .that fan always runs when the AC is engaged. if the fan isnt turning.. then most likely its faulty.

revs definitely dip on mine btw

 

[Chicayne]

There's a guy in Kenwyn that does aircon repairs, diagnostics and just about everything ac concerned.

He completely reconditioned my ac compressor and had another ac also sorted by him.

I can forward you his digits if you're interested to go see him.

Perfect, please forward me his digits.

 

[Cape_Tonian]

There's a guy in Kenwyn that does aircon repairs, diagnostics and just about everything ac concerned.

He completely reconditioned my ac compressor and had another ac also sorted by him.

I can forward you his digits if you're interested to go see him.

Perfect, please forward me his digits.

This guy is really good.

Everyone calls him "Kalla"

084 812 9548

You can tell him Clive with the black coupe gave you his details, good luck bud.