E46 Air-Conditioning Troubleshooting

[Zound]

Thanks for all the responses guys, I really appreciate it!

I agree that taking it to a specialist is probably the safest and wisest thing to do, but being a student, budget is tight so I'm going to first exhaust all DIY avenues before I take it to an AC specialist.

A couple of days ago I followed a couple of your suggestions and decided to remove and clean the Heater valve. It wasnt in too poor of a condition but I cleaned the oxidation off of the shaft and applied some grease. After installing it back in the car, the AC seems to respond quicker, but has not remedied the initial problem.

As mentioned, the left hand side vents are working correctly and will blow hot and cold air, but the right hand side vents will only blow ambient temperature and engine air. When I say left hand side, this includes the left center vent and correspondingly the right hand side includes the right hand center vent. I am fully aware of the 3 blue dots pre-requisite for cold air.

After doing the Freon recharge and the heater valve, the left hand side is fully capable of blowing ice cold air so I dont believe the system is low on refrigerant or that the compressor is struggling.

My best guess at the moment is that there is some "stepper" motor that is no longer functioning which operates the flaps for the right hand side of the vehicle.

Has anyone ever investigated these stepper motors or knows where they are located?

 

[ChefDJ]

Sounds like the final stage resistor, located behind the cubby hole (I stand to be corrected) like where the one on the E39 is.

I still need to do mine as I can't get the aircon to blow cold over the footwell areas.

 

[Maljan]

AFAIK the blower motor resistor will do weird things to the fan speed if it is broken.

 

[Blue Shirt]

The final stage resistor has nothing to do with air distribution, it controls the blower motor speed.

If the problem is with the stepper motors in the HVAC housing, the entire dash has to be stripped to get the HVAC housing out. It is a huge job.

I have learned with a/c systems to trust the professionals. If it has too little gas or too much gas, all sorts of weird things can happen.

Take the car to Icematic, they will put in the correct quantity of refrigerant, leak-test and troubleshoot any other faults for you. It will save you a lot of time and unnecessary work.

 

[Waseem 333i]

The final stage resistor has nothing to do with air distribution, it controls the blower motor speed.

If the problem is with the stepper motors in the HVAC housing, the entire dash has to be stripped to get the HVAC housing out. It is a huge job.

I have learned with a/c systems to trust the professionals. If it has too little gas or too much gas, all sorts of weird things can happen.

Take the car to Icematic, they will put in the correct quantity of refrigerant, leak-test and troubleshoot any other faults for you. It will save you a lot of time and unnecessary work.

I am with Blue Shirt. Just take it to a pro and have him check the system. For checking they usually don't charge.

 

[Loom]

I have the same problem. Can anyone recommend a professional in Potchefstroom?

 

[akajee]

I wonder if a diagnostic will identify the cause?

 

[Zound]

I have already tried with my handheld OBD diagnostic machine, but the unit didn't pickup anything on the AC side. Im busy installing INPA and Rheingold which should give me a more conclusive answer. At the moment, I just can't seem to find my OBD-USB cable :skit: turning the house upside down trying to find this thing!

 

[Zound]

Coming up to the December month and I want this sorted ASAP. I'm thinking of taking the car to "Independent Car Radio and Air Conditioning" situated in Centurion. They advised me that it would cost approximately R350 for diagnostics (Or essentially the cost if I refuse the Quote).

They seem to be affilated with Mahle-Behr AC systems, of which I have only had good experiences with, regarding their other line of BMW spares.

Anybody have experience with these guys?

I want to avoid being fooled into thinking this is simply a low refrigerant issue and being rushed R600 or so for a quick refill

 

[ChefDJ]

I still recommend Pit Auto Tech in Meadowdale. They have never disappointed me.

 

[Blert]

Coming up to the December month and I want this sorted ASAP. I'm thinking of taking the car to "Independent Car Radio and Air Conditioning" situated in Centurion. They advised me that it would cost approximately R350 for diagnostics (Or essentially the cost if I refuse the Quote).

They seem to be affilated with Mahle-Behr AC systems, of which I have only had good experiences with, regarding their other line of BMW spares.

Anybody have experience with these guys?

I want to avoid being fooled into thinking this is simply a low refrigerant issue and being rushed R600 or so for a quick refill

have you tried cleaning the heater valve as i said earlier in the thread?

 

[Fordkoppie]

Coming up to the December month and I want this sorted ASAP. I'm thinking of taking the car to "Independent Car Radio and Air Conditioning" situated in Centurion. They advised me that it would cost approximately R350 for diagnostics (Or essentially the cost if I refuse the Quote).

They seem to be affilated with Mahle-Behr AC systems, of which I have only had good experiences with, regarding their other line of BMW spares.

Anybody have experience with these guys?

I want to avoid being fooled into thinking this is simply a low refrigerant issue and being rushed R600 or so for a quick refill

They are brilliant.

Specializes more in Ford/Mazda, but we have had nothing but good service from them. Roger Rouessart is the main brain over there.

 

[Zound]

Coming up to the December month and I want this sorted ASAP. I'm thinking of taking the car to "Independent Car Radio and Air Conditioning" situated in Centurion. They advised me that it would cost approximately R350 for diagnostics (Or essentially the cost if I refuse the Quote).

They seem to be affilated with Mahle-Behr AC systems, of which I have only had good experiences with, regarding their other line of BMW spares.

Anybody have experience with these guys?

I want to avoid being fooled into thinking this is simply a low refrigerant issue and being rushed R600 or so for a quick refill

have you tried cleaning the heater valve as i said earlier in the thread?

I did to no avail. However I did notice that the little rubber seal inside the device appeared rather perished. I just did a quick test, while running the AC on full blast, I clamped the hose coming from the heater valve going into the cabin. If the heater valve was faulty and was stuck open, then this should have presented cold air and the solution. Unfortunately nothing changed and the one side still blows much warmer air. I plugged in Rheingold and monitored the statuses of various component temperatures. After 10-15 minutes with the AC on max cold, the system could only bring the interior temperature down to 22.5 degrees celcius... The mystery continues

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Coming up to the December month and I want this sorted ASAP. I'm thinking of taking the car to "Independent Car Radio and Air Conditioning" situated in Centurion. They advised me that it would cost approximately R350 for diagnostics (Or essentially the cost if I refuse the Quote).

They seem to be affilated with Mahle-Behr AC systems, of which I have only had good experiences with, regarding their other line of BMW spares.

Anybody have experience with these guys?

I want to avoid being fooled into thinking this is simply a low refrigerant issue and being rushed R600 or so for a quick refill

They are brilliant.

Specializes more in Ford/Mazda, but we have had nothing but good service from them. Roger Rouessart is the main brain over there.

Thanks, I'll give them a try then!

 

[Fordkoppie]

I clamped the hose coming from the heater valve going into the cabin. If the heater valve was faulty and was stuck open, then this should have presented cold air and the solution.

That does not completely eliminate a possible stuck valve, because you have a massive reserve of hot water in the system even if you clamp the hose.

Did you do this from cold, or when the car was already hot?

If the car is stone cold in the morning, and you start the engine plus immediately switch on the AC, does it blow cold air then on the right side?

 

[Zound]

I clamped the hose coming from the heater valve going into the cabin. If the heater valve was faulty and was stuck open, then this should have presented cold air and the solution.

That does not completely eliminate a possible stuck valve, because you have a massive reserve of hot water in the system even if you clamp the hose.

Did you do this from cold, or when the car was already hot?

If the car is stone cold in the morning, and you start the engine plus immediately switch on the AC, does it blow cold air then on the right side?

I did this from cold, the car had been standing in the garage for over 24 hours. Upon immediately starting the car, the same issue resides... So I don't believe the heater valve is the primary culprit here?

 

[Blert]

i think it is personally

due to the fact you not loosing gas, compressor is working and you getting some what room temperature air out the vents. aswell as the different temps from the different vents.

do you have someone that can swop out their heater valve to test with?

 

[Zound]

I have a friend with an E46 320i (M54B22) but I've got a feeling that he has the dual solenoid heater valve and not the single solenoid variant such as mine...

 

[Zound]

So swapped in a friends Heater control valve and absolutely no change whatsoever.

 

[Zound]

Whipped out Rheingold and decided to do a pressure test.

Measured 2.1 Bar on the Low side and 8.3 Bar on the High side.

Rheingold suggests an ideal range of 1.0 to 2.2 bar for the low side and 12-22 bar for the high side.

So therefore by that comparison I have low pressure on the High side and Rheingold suggests that I have insufficient fill quantity of refrigerant and need to have my system evacuated and refilled with oil and refrigerant.

Since I have already performed a refill (perhaps not up to professional standards) I believe I have a leak and will need to perform some kind of leak detection experiment to find out where it is coming from.

After reading a couple forums, I believe that my problem of half cold half warm is the plastic door located inside the heater box which is not shutting off ambient temperature air entering through the vents. I determined this by a quick thermometer reading of the vents. Running the AC system at full blast (16 and max blower) for 10 minutes, the left side vent measured 18.5 Celcius and the right side vent measured 25.5 Celcius, coincidentally the exact same temperature as the outside temperature!

I think I'm getting closer to solving this gremlin...

 

[DIY enthusiast]

Whipped out Rheingold and decided to do a pressure test.

Measured 2.1 Bar on the Low side and 8.3 Bar on the High side.

Rheingold suggests an ideal range of 1.0 to 2.2 bar for the low side and 12-22 bar for the high side.

So therefore by that comparison I have low pressure on the High side and Rheingold suggests that I have insufficient fill quantity of refrigerant and need to have my system evacuated and refilled with oil and refrigerant.

Since I have already performed a refill (perhaps not up to professional standards) I believe I have a leak and will need to perform some kind of leak detection experiment to find out where it is coming from.

After reading a couple forums, I believe that my problem of half cold half warm is the plastic door located inside the heater box which is not shutting off ambient temperature air entering through the vents. I determined this by a quick thermometer reading of the vents. Running the AC system at full blast (16 and max blower) for 10 minutes, the left side vent measured 18.5 Celcius and the right side vent measured 25.5 Celcius, coincidentally the exact same temperature as the outside temperature!

I think I'm getting closer to solving this gremlin...

Hi
I also have the same problem, did you get the problem sorted? Please share.