AC and cabin air issues.

[-Matt-]

My AC is currently working and blows out cold air pretty well however after it has been on for a while (and especially when I take my foot off the accelerator) it begins to make a whining noise somewhere up in the engine bay.

Do you think a simple re-gas is going to fix this or do I need to replace the compressor or compressor clutch system? (I don't really want to re-gas twice if I can avoid it).

Is it possible to oil and service the compressor/clutch without discharging the gas system?

What about just replacing the belt and tensioner?

As a secondary issue the air coming from my blowers has quite a stale smell. I know this is a common problem but the odd thing is it doesn't seem to smell when the AC is on, only when the normal air blowers are working. Other posts I have seen normally say the smell is associated with the AC?

I plan to replace the cabin air filter this weekend (I expect the current one is >140K miles old)! Hopefully this will increase air flow slightly but will it also fix the bad smell?

[-Matt-]

Just seen that at Halfords you can buy this measure and charge stuff for £39.99

http://www.halfords.com/wcsstore/HalfordsConsumerDirect/images/catalog/00009564.jpg

and you get this Comma Aircon Cleaner free:

http://washford.scene7.com/is/image/Washford/400-786335?$prod$

Does that seem like a good deal? ..and would it be enough to charge my system up twice if required?

Has anyone tried using this stuff before and was it effective?

[-Matt-]

Bump ^^^

I am starting to convince myself that the noise is caused by the ac compressor clutch since it only seems to occur once the low temperature set point is achieved.

As a separate issue I think I probably also need a gas top up soon.

Apparently the ac clutch can be replaced without discharging the ac system - has anyone done this or know where I can find a diy? I will probably also replace the belt whilst I am doing it.

[Jim Spence]

I've recharged a few vehicles with the 134A kit you've pictured. It's easy to do, but you shouldn't do it all the time without getting your entire AC system checked by a professional.

[zachiepie]

Is the noise like a bird chirping sound? I wonder if its coming from the fan blower. Does it make the noise when the heater, or ac, or straight up vent is on?

[-Matt-]

Thanks for the replies,

The noise is very definitely related to the air conditioning - not the fan blower. It stops immediately when I switch off the ac (I have the climate control module).

The main noise is a droning/whining noise that varies with engine revs. There is also some gurgling (maybe chirping) type noises from the ac system.

I currently hope that it is just low ac fluid - but I would like someone to confirm this.

What I think is happening is as follows... When the system has been off for a while the fluid settles in the main reservoir. Once turned on the compressor pumps the fluid and everything works fine for a while. Then (because the fluid is low) the compressor runs out of fluid to pump. It gets an air pocket and starts making the droning and gurgling noises as the compressor turns.

Does this sound like a plausible cause of the problem? If this is the case then re-gassing should fix the problem right? I'm hoping this is all that the problem is and that the compressor itself is fine.

Can anyone who has had similar issues let me know if I'm on the right track.

Thanks

[-Matt-]

Jim, I think I'm going to give the kit a try. Do you remember what pressure the system is supposed to be charged to? How do you make sure you gat the right amount of oil?

[Jim Spence]

Matt, just follow the directions on the can. You hook your hose to the system (it can only hook to the proper port) and depress the nozzle, turning the can from 9:00 to 12:00 every few seconds. That way you get both freon and oil into the system. Release the button and look at the gauge; when it's in the blue, it's properly charged.

[-Matt-]

Well, I gave it a try this morning. The gauge read in the blue right from the start, however I followed the directions thinking I would get the needle up to the top of the blue section.

The needle never really seemed to move - is there an over pressure valve that prevents over filling? If so what I have probably just done is add a bit more oil and very slightly re pressurised the gas.

On my drive to work I kept the ac on full all the way and heard no strange noises so far. I did arrive feeling pretty cold though!

I did the anti-smell spray too - it seems to be pretty powerful smelling stuff. I hope it is doing some actual good at cleaning the system rather than just being an air freshener.

I would hesitate to recommend this measure and charge system to others because there seems to be a lot of uncertainty in the quantity of gas and oil you are adding. I wouldn't be surprised if this comes back and bites me in the ass next time I have the ac properly serviced. It seems to be working so far so hopefully this will work as a short term fix - I will keep you posted.

[Jim Spence]

As long as the gauge shows in the blue, you're good. You didn't overfill it.

[-Matt-]

The only thing I am worried about now is the ratio of gas to oil. I think it would be easy to add too much oil. Anyway - it all seems fine at the moment.

I have just ordered a replacement cabin air filter from a UK company called Puravent...

http://www.puravent.co.uk/filters/dispfilter.pl?id=18

It looks like it has been made to a high quality and the price seems comparable to the dealer price. Has anyone else used these filters before? Are they good?

[-Matt-]

Puravent filter arrived and was fitted yesterday. I can't understand why BMW made it so difficult to get the filter in and out. In my rhd car the steering column seems to block the path that the filter needs to take, even though the filter is articulated.

Anyway the filter is now in and is performing great. I'm really pleased with the quality and with the service I received from Puravent. I would highly recommend them to anyone - particularly if you live in the UK and can take advantage of the free delivery.

[ryder23]

I just had my AC evacuated and filled, it works well again. AC temp gets down to 40F

Before, I tried to refill it myself and it did not make things colder. The lowside pressure was reading 30psi and I kept charging hoping to get about 40psi. During the charge the pressure held steady at 30psi. All of the sudden it shot up to 80psi on the lowside!!!!! The highside was messed up at 300psi when it should be sitting at 150psi (Garage measured highside for me when I brought it in). Luckily this did not do any damage.

Word of advice, don't charge it yourself. Get a full evacuation just as the Bentley manual suggest and warns.
Oh yes, lowside should be 30psi on my car and 150psi on highside.