[-KingJames-]

I recently took my 17 F34 330i GT to the dealer to get the AC system charged due replacing a broken AC line. They charged the system but found the compressor to not kicking on for very long and dragging. They quoted me almost $2k to replace the compressor. Of course I declined.

So when turning on the AC, the compressor turns on for a few seconds and then turns off. I see the clutch kicking in when initially turning it on and it spins, but like the dealer said, it turns off not too long after. No cool air is coming out of the vents with the AC on.

Anyone have any experience with this? Could it be something else or is the compressor toast and needs replacing? Could it be the AC relay or replacing some minor part of the compressor?

[Wires]

I've had issues where I had the fan level at the lowest setting which caused the system to freeze up, and the compressor to turn off.

Others have mentioned the high pressure switch (I think it was the high, not low...) fails causing symptoms like you are describing. That is a simple and cheap fix if that is the case.

[Wgosma]

the Freon carries the lubricant for the compressor, so it would seem possible that if the a/c system was operated with zero or low Freon that the bearings and seals in the compressor may have been damaged.

[-KingJames-]

Originally Posted by Wires

I've had issues where I had the fan level at the lowest setting which caused the system to freeze up, and the compressor to turn off.

Others have mentioned the high pressure switch (I think it was the high, not low...) fails causing symptoms like you are describing. That is a simple and cheap fix if that is the case.

What is the "cheap" fix?

[Wires]

Its replacing that failed pressure switch (if it's faulty). It just unscrews with a single connector on the top.

[-KingJames-]

Originally Posted by Wires

Its replacing that failed pressure switch (if it's faulty). It just unscrews with a single connector on the top.

What switch are you referring to? On the AC compressor?

[Wgosma]

Originally Posted by -KingJames-

What switch are you referring to? On the AC compressor?

See attached pic, item #4 I believe is what above poster is referring to.

https://www.fcpeuro.com/products/bmw...181464#reviews

Good luck/Bill

[Wires]

Yes, #4. I've seen other threads where that is a common failure which forces the compressor off since you've lost the safety check.

[-KingJames-]

Originally Posted by Wires

Yes, #4. I've seen other threads where that is a common failure which forces the compressor off since you've lost the safety check.

Okay, so thats the AC line I replaced. That whole line, I bought a used off ebay that included the sensor. I may have the old pressure sensor from the broken line.

Today I checked the AC and compressor and it was working after not working for 2 weeks. The clutch was engaged and spinning with the AC from a cold start. The radiator fan wasn't spinning, im guessing thats normal when you start your car in the morning even if AC is on? Anyways ill continue to monitor it and if it stops working ill see if I can replace that sensor.

[-KingJames-]

Originally Posted by Wgosma

See attached pic, item #4 I believe is what above poster is referring to.

https://www.fcpeuro.com/products/bmw...181464#reviews

Good luck/Bill

Thanks, I replaced that entire AC line since it was damaged. I'll see if I can find the old sensor from the damaged line.

[Wires]

The AC compressor runs and different times to keep the seals lubricated otherwise they dry out and you lose refrigerant. In "olden days" the compression would kick in with the windshield defroster on some brands.

I've never looked at mind to see when it's cycling or not, so I'm not much help there.

[Wgosma]

Some compressors are 'variable volume' design (like in my X3)....they are 'continuously engaged' so to speak, always running.

But after reading this F30 forum for a while it seems compressors in these sedans are older style.

[-KingJames-]

Yes I've read that too, but I'm still not sure how these compressors are supposed to function properly.

As for the pressure sensor, does the refrigerant from the AC lines have to be vacuumed out prior to replacing it or can I go ahead and replace it without vacuuming it out?

[Wires]

The sensor SHOULD just unscrew with no need to vent refrigerant (don't quote me, but that is my understanding from what I've read). There was a TSB somewhere on this forum that talked about it.

[-KingJames-]

So with the AC on, the cool air from the vents comes and goes. Seems the compressor engages and then disengages constantly. There should be constant cold air coming with the AC on right?

[Wgosma]

Originally Posted by -KingJames-

So with the AC on, the cool air from the vents comes and goes. Seems the compressor engages and then disengages constantly. There should be constant cold air coming with the AC on right?

It's normal for compressor to engage/disengage when a/c in use. But generally it should not be cycling on/off at a high rate/frequency.

You should feel a reasonably constant stream of cool air entering the cabin; no major air temp swings.

[pshovest]

How long was the AC system discharged w/broken line?
Your compressor has both a magnetic clutch and a capacity control valve.
The compressor should be able to run continuously under all but extreme light cooling loads, like 40F temps and sustained high vehicle (and therefore compressor) speeds.
You need to scan the IHKA module with ISTA. Hard to believe the dealer didn't do this.
Bad pressure switch, bad evap temp sensor, bad clutch, stuck capacity control valve, bad electrical connection(s) and likely other issues could cause short cycling of clutch.
I would not attempt to change pressure switch/sensor w/o discharging system.

[pshovest]

delete duplicate

[-KingJames-]

Originally Posted by pshovest

How long was the AC system discharged w/broken line?
Your compressor has both a magnetic clutch and a capacity control valve.
The compressor should be able to run continuously under all but extreme light cooling loads, like 40F temps and sustained high vehicle (and therefore compressor) speeds.
You need to scan the IHKA module with ISTA. Hard to believe the dealer didn't do this.
Bad pressure switch, bad evap temp sensor, bad clutch, stuck capacity control valve, bad electrical connection(s) and likely other issues could cause short cycling of clutch.
I would not attempt to change pressure switch/sensor w/o discharging system.

For months, but car wasn't running. Just recently fixed it up. ill see if I can get someone to scan the IHKA module

[-KingJames-]

Using my Veepeak and phone to scan for DTC and got this code:

Fault 801224: Air conditioning compressor: Shut-down due to excess pressure in refrigerant circuit

[Wgosma]

Originally Posted by -KingJames-

Using my Veepeak and phone to scan for DTC and got this code:

Fault 801224: Air conditioning compressor: Shut-down due to excess pressure in refrigerant circuit

Interesting, not certain on cause. one thought: if Freon flow is restricted somewhat in the circuit the compressors operation may well be pushing pressure above allowable levels, thus the fault. Or maybe it's simply fact that system was over-filled with Freon.
May need Mr. A/C specialist to pinpoint issue.

[Wires]

That's either a faulty high pressure sensor or an actual over-filling of the refrigerant in the system.

Or a blockage as mentioned above. That is possible if it sucked in crude with the broken line. You'll need to take it somewhere they can hook the gauges to it to properly diagnose.