My wife is HOT!!!!!!! - Page 3

Beamernewbie · #1 05-22-2017, 09:32 AM

Clutch appears to be working properly. The engine rev apparently doesn't work every time either. Sometimes you can turn it on after driving it awhile and it cools immediately and then other times it doesn't, but it never cools immediately after it's been parked for a few hours. This is very frustrating.

80stech · #2 05-22-2017, 11:02 AM

Quote:

Originally Posted by Beamernewbie

Clutch appears to be working properly. The engine rev apparently doesn't work every time either. Sometimes you can turn it on after driving it awhile and it cools immediately and then other times it doesn't, but it never cools immediately after it's been parked for a few hours. This is very frustrating.

So clutch is working and compressor is turning when it's not cooling ? Maybe the variable displacement valve is sticking. I think you are going to need someone to check this for you.

Beamernewbie · #3 05-25-2017, 04:45 PM

So now the AC doesn't cool at all!!!! My wife came home yesterday sweating worse than a hooker in church on Sunday morning. The aux fan is working however I don't know if it all the time. The compressor clutch is engaging, at least when I look at it. Soooooooooo any ideas at this point? I really don't want to go to a BMW dealer because it seems like nobody ever leaves there without a 2k less in their bank account than when they arrived.

crystalworks · #4 05-26-2017, 01:58 AM

Quote:

Originally Posted by Beamernewbie

So now the AC doesn't cool at all!!!! My wife came home yesterday sweating worse than a hooker in church on Sunday morning. The aux fan is working however I don't know if it all the time. The compressor clutch is engaging, at least when I look at it. Soooooooooo any ideas at this point? I really don't want to go to a BMW dealer because it seems like nobody ever leaves there without a 2k less in their bank account than when they arrived.

^I just replaced a compressor in my mom's FX35 Infiniti for exactly the symptoms you are describing. It used to cool intermittently and continued to get worse and worse until finally no cooling at all. Low side was reading too high and high side was reading too low. Not sure what in the compressor failed... but it cools great now after replacement (along with Xpansion valve and receiver dryer).

How any miles are on your X? Original compressor?

Beamernewbie · #5 05-26-2017, 06:43 AM

146k

upallnight · #6 05-26-2017, 06:56 AM

Quote:

Originally Posted by crystalworks

^I just replaced a compressor in my mom's FX35 Infiniti for exactly the symptoms you are describing. It used to cool intermittently and continued to get worse and worse until finally no cooling at all. Low side was reading too high and high side was reading too low. Not sure what in the compressor failed... but it cools great now after replacement (along with Xpansion valve and receiver dryer).

How any miles are on your X? Original compressor?

Some of the old compressors uses reed valves which over time after many cycles they just fail.

upallnight · #7 05-26-2017, 06:53 AM

Quote:

Originally Posted by 80stech

So clutch is working and compressor is turning when it's not cooling ? Maybe the variable displacement valve is sticking. I think you are going to need someone to check this for you.

I was under the impression that variable valve compressors were clutchless. Since the valve varies the displacement of the compressor, there is no need for a clutch. The compressor is always turning, but if ac cooling is not required, the valve varies the displacement to almost zero, so there isn't any drag on the engine. When ac is required, the valve increases the displacement of the compressor so that refrigerant is pumped from the low side to the high side thus providing the cooling effect requested.

phathom · #8 05-26-2017, 11:35 AM

Quote:

Originally Posted by upallnight

I was under the impression that variable valve compressors were clutchless. Since the valve varies the displacement of the compressor, there is no need for a clutch. The compressor is always turning, but if ac cooling is not required, the valve varies the displacement to almost zero, so there isn't any drag on the engine. When ac is required, the valve increases the displacement of the compressor so that refrigerant is pumped from the low side to the high side thus providing the cooling effect requested.

This would explain the AC pulley always spinning in its entirety for me then. I don't mean to hijack the thread, but me and OP are having the same issue.
If it's a variable valve that always spins, does that mean there would be no shim to ad or remove to adjust the air gap as that's a clutch related part?
I'm probably going to tear into mine today if there's a possibility of me being able to fix it like that, otherwise I'll probably have to bite the bullet and get a new compressor. I know my aux fan and hvac panel are fine and not the problem.
Is therr anyway to clean out the valves in the compressor, like if they're getting stuck and that's why they intermittently work?

upallnight · #9 05-26-2017, 12:42 PM

Quote:

Originally Posted by phathom

This would explain the AC pulley always spinning in its entirety for me then. I don't mean to hijack the thread, but me and OP are having the same issue.
If it's a variable valve that always spins, does that mean there would be no shim to ad or remove to adjust the air gap as that's a clutch related part?
I'm probably going to tear into mine today if there's a possibility of me being able to fix it like that, otherwise I'll probably have to bite the bullet and get a new compressor. I know my aux fan and hvac panel are fine and not the problem.
Is therr anyway to clean out the valves in the compressor, like if they're getting stuck and that's why they intermittently work?

On some variable valve compressor, the valve can be replaced. I believe the valve in a BMW with the variable compressor can be replaced. But the refrigerant in the system will have to be recovered before replacing the valve. Unless you have the equipment and knowledge to recover refrigerant from a close system, best to take it into an AC shop.

phathom · #10 05-26-2017, 02:08 PM

So I did some searching and found that the kicking on at 4k rpms symptom was likely due to low pressure in the system. Our variable displacement compressors use the refrigerant pressure to regulate the displacement of the compressor. This makes sense then. Low pressure would make it not adjust to the right displacement to cool. Revving the engine to 4k would spin the pulley and clutch faster and increase pressure enough for it to work.
So I went to the store and bought another can of r134a. When I started filling it up, the aux fan revved up really high like if I pulled the plug. I filled it up to about 43psi and it seems happier like this in terms of kicking on, but it still isn't really cold like I'm used to, that seems to come and go. Perhaps it needs to be fully purged and then fly charged to spec with both high and low side gauges instead of just using a low side gauge/filler combo. I'm going to see about renting a set of gauges from Auto zone to get it really tuned in, but I think the problem here was definitely the pressure of the system since the clutch was engaging with the ac on and the aux fan was working.
I'll update, but this may be our problem, possibly because we're not used to working with variable displacement internally regulated compressors. Older cars had a fixed displacement compressor, which was much simpler and as long as the clutch engaged it would pump. These require a set pressure to determine the displacement and how much to pump on top of it.

Edit: drove it a bit. It seems to be doing better, especially while moving. I checked the pressure again. When filling it, it was shaky and would go between 43 and 55 as the compressor cycled. After driving and checking it again it's sitting solid at 37psi. I'll see how it acts after it sits for a few hours. That seems to be when it's had problems kicking on.