E46 Air-Conditioning Troubleshooting

Hi all,

I am a DIY enthusiast but when it comes to AC, I am a complete novice.

The car in question is a 2001 BMW E46 330i Manual, with 250 000Kms.

Upon receiving the car, I noticed that the AC only blew slightly cold on the passenger side (left hand side) while the drivers side would only blow ambient temperature air.

I checked out a couple forums, mostly in the States regarding the subject matter, which indicated to me that my AC system could possibly be low on R134a Freon gas, and subsequently requires a re-gas/re-charge.

I bought a 1KG can of R134a, adapters for the low-pressure and high-pressure side, a pressure reading gauge and the corresponding hoses.

As I understand it, I need to re-charge my AC system to a certain pressure. Now according to this diagram, and at 18 degrees celcius, I need 25-35psi on the low side.


Now, obviously I was hoping my system would be somewhere on the low side, such as 20-25psi. So I did a pressure test with the AC on full blast, and the gauge read 30psi

That number is smack in the middle of the suggested acceptable pressure levels.

I've also noticed that the AC has deteriorated slightly, since acquired about a month ago, in that the AC is barely existent on the passenger side now.

Is there an E46 specific pressure for the low side that I am not aware of?
Any advice regarding further troubleshooting?

FYI: The AC was tested with three blue dots on the vent control, the blower set to max fan speed and 16 degrees Celsius. The compressor also seems to be operational as it has a distinct kick and sound when activated via the snowflake button.

Give it the max and add that little 5psi and see what happens

Brought out my CarSoft OBD2 Diagnostic and have started hunting down any related faults. Found an AUC Sensor error, which I have fixed and cleared. Have not driven the car yet and/or tested the AC, but will report back once I have done so.

So decided to do the AC Freon recharge. After emptying about half the bottle, the left hand side or passenger side vents will blow ice cold air. The drivers side got colder but, no where near the icy cold temperature of the passenger side. Using a digital thermometer, there is an evident 4 degree Celsius difference between the two vents, throughout the entire temperature range. So the problem is far from solved, however it is nice to have the AC a bit colder now. Interesting note: after charging the system with new freon, the pressure on the low side remained exactly the same. 30psi. So provided that I have no leaks in my AC system, I can definitely say that the Bmw e46 AC system is quite sensitive to small pressure increments, or simply that the AC system must hold quite a large volume of refrigerant.

If anybody has any insights into the residing issue, please do share:bangdesk:

Zound said:

So decided to do the AC Freon recharge. After emptying about half the bottle, the left hand side or passenger side vents will blow ice cold air. The drivers side got colder but, no where near the icy cold temperature of the passenger side. Using a digital thermometer, there is an evident 4 degree Celsius difference between the two vents, throughout the entire temperature range. So the problem is far from solved, however it is nice to have the AC a bit colder now. Interesting note: after charging the system with new freon, the pressure on the low side remained exactly the same. 30psi. So provided that I have no leaks in my AC system, I can definitely say that the Bmw e46 AC system is quite sensitive to small pressure increments, or simply that the AC system must hold quite a large volume of refrigerant.

If anybody has any insights into the residing issue, please do share:bangdesk:

Click to expand...

Al I know is That I had this problem and I took it to a place where they drained the system and connected a Vacuum pump to the system to vacuum the complete system. After that they added new oil and regassed it. And it worked like New after the Aircon service. You need to get it hooked up to one of the new fancy machnies that do everything of the above

Iceman007 said:

Zound said:

So decided to do the AC Freon recharge. After emptying about half the bottle, the left hand side or passenger side vents will blow ice cold air. The drivers side got colder but, no where near the icy cold temperature of the passenger side. Using a digital thermometer, there is an evident 4 degree Celsius difference between the two vents, throughout the entire temperature range. So the problem is far from solved, however it is nice to have the AC a bit colder now. Interesting note: after charging the system with new freon, the pressure on the low side remained exactly the same. 30psi. So provided that I have no leaks in my AC system, I can definitely say that the Bmw e46 AC system is quite sensitive to small pressure increments, or simply that the AC system must hold quite a large volume of refrigerant.

If anybody has any insights into the residing issue, please do share:bangdesk:

Click to expand...

Al I know is That I had this problem and I took it to a place where they drained the system and connected a Vacuum pump to the system to vacuum the complete system. After that they added new oil and regassed it. And it worked like New after the Aircon service. You need to get it hooked up to one of the new fancy machnies that do everything of the above

Click to expand...

Where did you go and what did it cost you, may I ask?

Try Yskop

Yskop Refrigeration

Louis Trichardt St
0084 Rietfontein Pretori

Phone: 012 3313678

They fixed mine.

So the AC has been deteriorating again, to the point where not even setting 16 degrees on the climate control will cool the car sufficiently. This is concerning, as it makes me think I have a leak.

While driving to varsity today I felt a couple drops of liquid drop onto my feet. I thought I was imagining things but then it happened again when I went around a sharp bend. Just a couple drops, no large quantities.

What pipes run below the steering column and instrument cluster? Surely only AC lines?

I'm gonna get stuck into the AC as soon as I get some free time. Will be investigating stepper motors and the heater control valve, and obviously the new leak!

Any advice?

On my car , it was the vulve in the compressor
It has a screen on it , and as the screen gets clogged it decreases its ability to pump and thus lowering the "cool air " coming out the vents . I had the vulves replaced and it works as good as new now. ( I was told by every single big name aircon company in dbn that I need to replace the compressor ) Found a guy who knew these compressors and he fixed it

You could also have incorrect levels of gas or oil , I also suggest you take it to one of these guys with the correct equipment and have them look at it . Might save you a whole lot of trouble. You dont want to damage the system or mess up any of its components.

I gave up one mine. Got the same car.

@ Zound

Brought out my CarSoft OBD2 Diagnostic and have started hunting down any related faults. Found an AUC Sensor error, which I have fixed and cleared. Have not driven the car yet and/or tested the AC, but will report back once I have done so.


I have the same error, how did you fix it ?

Charlie Brown said:

@ Zound

Brought out my CarSoft OBD2 Diagnostic and have started hunting down any related faults. Found an AUC Sensor error, which I have fixed and cleared. Have not driven the car yet and/or tested the AC, but will report back once I have done so.


I have the same error, how did you fix it ?

Click to expand...

I removed the AUC sensor, replaced the old filter with some aquarium filter whool and put it back together. The fix only lasted about a week and is now a constant fault again.

---

Bmw.wp said:

I gave up one mine. Got the same car.

Click to expand...

Ill eventually find the crux of the problem. Just a process of elimination which is unfortunately very time consuming and tedious.

Nick, the water leaking onto your feet means the excess water the aircon makes is not draining out properly. Try clear all the necessary drainage areas. This happened on my Jetta and when they found the problem it looked like 10 years worth of leaves and what not had gunked up the system.

I only take my cars to Pit Auto Tech in Meadowdale near Germiston Makro. They were the ones who sorted the problem on the Jetta, and also the ones who saved me 5 grand when I bought the 5er with no working aircon. The dealer said to me that I can either collect the car that day without an aircon and get a refund of 5k on my deposit, or let them keep the car for another week or two to try and fix the aircon which they said was the compressor and the fan and I dunno what else.

Fetcher her that day, got my 5k in cash, took her to Pit Auto Tech the next day and they inspected, filled, tested and checked for leaks for I think it was 450 Mandelas at that stage, two years ago.

Thanks - I did something similar with some foam / sponge just to replace the material, not sure if the fault has come back, pretty sure it has.

I had mt aircon sorted recently on my e46. The heater valve was not shutting off. I found a small blue capacitor that fell off. Resoldered it back on then went back to the aircon guy. He checked the system with the machine and regassed. All is working well. I paid R680.

I do alot of DIY on my car but aircon is one thing i cant do because i dont have the equipment. It is very important to vacuum the system to get rid of moisture then refresh with new gas. If the method is not done correctly the compressor will fail.

I have a slightly different problem but also on the air con side (not really a problem but strange)

When I use the demister button, my windscreen does not clear up, only when I use the air con

It is mostly recommended to have the aircon on when demisting, even when using hot air.

Zound

if your checking the side vents what does your center two vents do?
are they blowing cold or hot when the cold hot adjustment thing is on 3 cold dots?

I had that problem where even if the aircon was on the side vents blew what seemed to be cold but the centre vents are little warmer.
I made a thread on here and Gizmo advised that the its the heater valve.

which is was you can check my thread to see what needs to be done.
http://www.bmwfanatics.co.za/showthread.php?tid=61011

its worth a try

[quote='H|]
Try Yskop

Yskop Refrigeration

Louis Trichardt St
0084 Rietfontein Pretori

Phone: 012 3313678

They fixed mine.
[/quote]


+1 on that. I have also had work done there. It's been more than two years ago and the car is still blowing cold.

Another good aircon shop in Pretoria is Icematic in La Montagne (012) 8030185.

The amount of refrigerant in the a/c system is determined by quantity (mass) and not by pressure. There are many variables that can affect the low/high pressures in the system but cooling capacity is determined by the amount of gas in the system.

It is possible to overfill the a/c system with refrigerant which will also affect cooling capacity negatively.