Probable air conditioning system problem

[denissef]

It started days ago, whenever I put the brakes to stop, this vibrating sound scared me and it only dissapeared when I took my foot off the brake, although sometimes it faded while I was at the red light. I think it is something related to the air conditioning system because I have tried going without the AC on and I have not had that problem again. What could it be?

The air conditionier cools well though, I have not had problems with that... yet...

Any thoughts, or suggestions?

[cali-ti]

does the sound/vibration occur once you've come to a complete stop? do you feel the vibration in your foot when you're braking?

[1996 328ti]

It started days ago, whenever I put the brakes to stop, this vibrating sound scared me and it only dissapeared when I took my foot off the brake, although sometimes it faded while I was at the red light. I think it is something related to the air conditioning system because I have tried going without the AC on and I have not had that problem again. What could it be?

The air conditionier cools well though, I have not had problems with that... yet...

Any thoughts, or suggestions?Weird one. Does it sound like a groaring sound?

http://www.318ti.org/tsbs/groaring.html

[96cali]

Could just be slightly low on coolant causing the compressor to cycle on/off. EZ thing to check.

[denissef]

does the sound/vibration occur once you've come to a complete stop? do you feel the vibration in your foot when you're braking?
Yes... Whenever I have to stop at a red light, it happens and of course it only happens when I have my AC on. I can say that I can feel some vibration on my foot, yeah but also it's like it is coming from the front of the car (where the engine is).

[denissef]

Could just be slightly low on coolant causing the compressor to cycle on/off. EZ thing to check.
The coolant.... how can you check that? I mean can I do it myself? I would surely do it myself if there's a way.

[denissef]

Weird one. Does it sound like a groaring sound?

http://www.318ti.org/tsbs/groaring.html
Hmm, this is interesting, yeah it produces a sound like that... It scared me the first time LOL!

[1996 328ti]

Hmm, this is interesting, yeah it produces a sound like that... It scared me the first time LOL!I heard this in 99 in Florida in my 98 ti. It was VERY hot inside the car. I started it up and cranked the A/C. It sounded like a lion's roar. At the time it was fixed under warranty.

[cali-ti]

odd ... what did they replace?

[denissef]

odd ... what did they replace?
what do you mean?

[cali-ti]

what do you mean?
sorry, that question was for steven :) sounds like he had a similar problem that was fixed under warranty and i'm wondering what part they replaced to fix it (as it might be the same problem part on yours).

[1996 328ti]

odd ... what did they replace?Expansion valve or something to do with the evaporation unit. It was a common problem several years ago. Many of us experienced it.

[denissef]

I heard this in 99 in Florida in my 98 ti. It was VERY hot inside the car. I started it up and cranked the A/C. It sounded like a lion's roar. At the time it was fixed under warranty.

Well... My car doesn't sound like a lion's groar literally but i have noticed that the thing/noise or whatever get stronger whenever I have my AC in higher settings. When I have it in the lowest setting it happens but not as strong as.
Today I was driving with AC on and stopped a couple of times, then the vibration happened and while it was happening I turned the AC off immediately and the sound/vibration stopped instantly.

[denissef]

sorry, that question was for steven :) sounds like he had a similar problem that was fixed under warranty and i'm wondering what part they replaced to fix it (as it might be the same problem part on yours).
Oh.. ok, I thought I was missing something :)
Who knows, I am going to do some research on that, to understand what's the connection with ,my problem...

[cali-ti]

so perhaps it's related to blower speed? but with the AC off and just the blower on it doesn't do it?

[denissef]

so perhaps it's related to blower speed? but with the AC off and just the blower on it doesn't do it?
No, with the AC off it doesn't do it. I don't know what's the blower though :/

[cali-ti]

what most people would probably call the fan (but then it can be confused with the fan used to cool the radiator). it moves the air through the heating/cooling system through the vents into the car and you control it via the fan/blower speed switch inside the car (same area as the temp dial, AC controls).

any way to narrow down what area the noise/vibration is coming from? have someone poke their head under the hood while you turn the AC on? i don't think we're going to narrow it down without more info.

[denissef]

what most people would probably call the fan (but then it can be confused with the fan used to cool the radiator). it moves the air through the heating/cooling system through the vents into the car and you control it via the fan/blower speed switch inside the car (same area as the temp dial, AC controls).

any way to narrow down what area the noise/vibration is coming from? have someone poke their head under the hood while you turn the AC on? i don't think we're going to narrow it down without more info.

Yeah I saw it yesterday and it is almost always on, and I have no problems with that, unless you know I have the A/C on.

[usagi]

I believe I have the same exact problem. Bought this car a few months ago and didn't bother to check the AC. Like you said, I have this propeller or turbine sound when coming to a stop or when turning the AC off. It's a low
propeller sound. It bothers me, but the AC is somewhat cool.

Did you get it fixed or what did you do with it? I asked some people and they say it's the fan in front of the radiator and that I need not to worry. Well, I'm still a bit worried, because I never heard that sound before in other cars.

[denissef]

Hi,
no i haven't got it fixed yet, but i took it to the shop and they told me that the sound seems to become from the dashboard, and it might be related with the vacuum pump (i think they called it that way) they recommended me to take it to a bmw service center because it was a specific problem. I will have to take it there soon.

[usagi]

I have a feeling it's the compressor now. I'm afraid to find out.