Passenger Sdie Aircon blowing hot air when select cold

[dreman77]

Hi,

My passenger side aircon blows hot air even though the selector is at cold. I;m guessing its the temperature sensor. The question is how do I get to it and verify that it is the cause of the fault.

The airflow seems very low - will need to change microfilter. Does my model have a cabin air filter?

I also have the antifreeze smell in the cabin. I'm guessing heater core.

thanks

[Tiger]

Heater valve is stuck. You need to loosen up the selenoid cover and tap repeatedly with hammer to loosen up the selenoid and then tighten the cover back down.

[dreman77]

Heater valve is stuck. You need to loosen up the selenoid cover and tap repeatedly with hammer to loosen up the selenoid and then tighten the cover back down.

Hi Tiger,

thanks. which solenoid cover are we talking about and where is it. I am totally new to bimmers and do not have my bently manual yet.

thanks

[Tiger]

On driver side by firewall... remove black plastic cover and you should see the heater hoses, etc.

[bubba966]

On driver side by firewall... remove black plastic cover and you should see the heater hoses, etc.

Not all E34's have that cover on the solenoids. Mine didn't, nor did a friend's 525iT.

[dreman77]

Not all E34's have that cover on the solenoids. Mine didn't, nor did a friend's 525iT.

There is a black box on both the lh and rh firewall. Mine is a rh drive. The one in front of the driver has 4 screws holding it down. Would it be that one?

[Tiger]

Look up heater valve online and compare it to your car.

[bubba966]

There is a black box on both the lh and rh firewall. Mine is a rh drive. The one in front of the driver has 4 screws holding it down. Would it be that one?

Nope, those boxes contain the fuses on one side, and the computers on the other. The one with the 4 screws is the computer box, and the other one is one of the fuse boxes. As your car is RHD, the drivers side has the computer, and the passengers side has the fuse box.

Here's some pics I took of the heater valve in my car both before (w/out the cover as it came from the factory) and after (after I got the mounting nuts and cover installed).

http://www.bimmernut.com/forum/showpost.php?p=310221&postcount=25

It should be noted that the heater valve is right next to the fuse box. Those pics are a bit close up and don't show the location of the valves very well.

[dreman77]

Nope, those boxes contain the fuses on one side, and the computers on the other. The one with the 4 screws is the computer box, and the other one is one of the fuse boxes. As your car is RHD, the drivers side has the computer, and the passengers side has the fuse box.

Here's some pics I took of the heater valve in my car both before (w/out the cover as it came from the factory) and after (after I got the mounting nuts and cover installed).

http://www.bimmernut.com/forum/showpost.php?p=310221&postcount=25

It should be noted that the heater valve is right next to the fuse box. Those pics are a bit close up and don't show the location of the valves very well.

Hi Bubba,

Thank you so much for the photos. I have found the heater solenoid and no, mine does not have a cover on it. It is also using the hex type nuts on it. Should i go and buy the proper caps? I will try knocking on the solenoid as soon as i can fix the erratic idling issue. Are the caps supposed to be torqued to any specific value?

[Tiger]

Just tight is enoguh... you have to loosen up the selenoid cap a bit so you can 'bounce' the selenoid when you taps on it repeatedly.

[bubba966]

Hi Bubba,

Thank you so much for the photos. I have found the heater solenoid and no, mine does not have a cover on it. It is also using the hex type nuts on it. Should i go and buy the proper caps? I will try knocking on the solenoid as soon as i can fix the erratic idling issue. Are the caps supposed to be torqued to any specific value?

Only reason to change the hex nuts out for the cap nuts is if you want to install the cover on the heater valve. The cover doesn't need to be on there. BMW must have decided to save a buck or two on some models and not install the cap nuts & cover.

Only reason I went through the trouble of doing it to my friend's Touring & my car is that it just looked like something was missing. It took a bit of work to figure out how to get the cover on when the car had the hex nuts as the part #'s for the cap nuts wasn't easy to find. It'd always bothered her from day one that it looked like that. And when I finally found my car it was just as annoying to me. But that's fixed now.

As I recall the nuts (either hex or cap) need to be torqued fairly lightly. It's easy to over torque them and snap the mounting posts off. And apparently you should loosen those up a bit when you're tapping on the solenoid to get it working again. I've not had the solenoid stuck yet, so I've not tried tapping it to get it going again.

[dreman77]

Hi,

My passenger side aircon blows hot air even though the selector is at cold. I;m guessing its the temperature sensor. The question is how do I get to it and verify that it is the cause of the fault.

The airflow seems very low - will need to change microfilter. Does my model have a cabin air filter?

I also have the antifreeze smell in the cabin. I'm guessing heater core.

thanks

hi,

i tapped the heater solenoid and nothing happened. The passenger side was still blowing hot air. So i decided to play with the switches on the aircon control. they were all to the extreme left. I moved the interior circulation switch switch to the right and i noticed air was blowing out from my foot area. The passenger side also started becoming cooler. It was not as cold as the driver side aircon but definitely not as hot as before. Is this the normal operation of the aircon?

Thanks

[Bimmerman]

I heard a story low gas pressure in the aircon system would automatically divert all gas to the drivers side only as a comfort/safety feature. Not 100% sure that applied to the e34's, though it is certainly the case on e39's/e46's etc.

[dreman77]

I heard a story low gas pressure in the aircon system would automatically divert all gas to the drivers side only as a comfort/safety feature. Not 100% sure that applied to the e34's, though it is certainly the case on e39's/e46's etc.

i see. well, i took out the microfilter today and boy was there alot of crud in there. It was filthy. Black in color too. Will bring it to the air con shop for a top up of gas and see how it goes.

Btw, while I was removing everything to remove the microfilter, i noticed this oily black substance on what i think is the evaporator hosing. There is a rubber piece there and it was covered i oil. Any ideas what this might be?

thanks