AC making funny sounds

[SenorTips]

Hello everyone I have a 2000 bmw 740i Sport and AC blows cold and works great car runs strong I just hit 130k on the motor. But every time I turn the AC on I hear a groggy sound
Im thinking I might have to Recharge it?
Also I'm starting to get light shaking of the car at speeds of around 30 to 40 mph and after that it stops.

[Mayorchuck]

If the air is cold, should not need a recharge. Not sure what groggy means but if it's gurgling, make sure it's draining on each side of the transmission. If it's more of a groan, could be the bearings on the fan motor.

[SenorTips]

Yes air is freezing cold and only takes a few seconds to get cold even on a hot day. It sounds more like a whining sound as if a jet engine was whining up and down Its weird lol Also when I turn the AC on my rpm jumps slightly and when I turn it off rpm back to normal
Driving with AC doesn't lack power or performance just doesn't sound normal

[Mayorchuck]

Idle change is normal. If the sounds is coming from the blower motor area, under the dash, and not from the engine bay, my guess is it's the bearings on the fan. Some info here towards the bottom of the page.

http://www.wibimmers.com/board/index...wer-motor-diy/

[Frankie]

...every time I turn the AC on I hear a groggy sound...

I have the same issue. The compressor makes a growling or low-frequency whirring sound, audible from inside the car (especially at idle). The system blows cold and I have no complaints other than the noise. I hope that doesn't mean the compressor is failing (bad bearings?).

[01740ISP]

I have the same noise and I am planning on having the system emptied and the refilled. Just won't happen for the next 3 months. This car is not leaving the garage for another 3 months.



-Messan

[Reflex]

Had it in my 2001. Emptied the entire system after pulling everything out for 20 minutes and then refill to the factory specs. Solved the problem for good. I now have it in my 2000 and will do the same. Strangely none of my 1998 E38s had this issue, both are facelift cars with the exact same symptom.

[racer2086]

Yes air is freezing cold and only takes a few seconds to get cold even on a hot day. It sounds more like a whining sound as if a jet engine was whining up and down Its weird lol Also when I turn the AC on my rpm jumps slightly and when I turn it off rpm back to normal
Driving with AC doesn't lack power or performance just doesn't sound normal

I have the same issue. The compressor makes a growling or low-frequency whirring sound, audible from inside the car (especially at idle). The system blows cold and I have no complaints other than the noise. I hope that doesn't mean the compressor is failing (bad bearings?).

You guys need to recharge your systems. When the refrigerant seeps out, some oil goes with it. But probably more importantly, less refrigerant, less oil flow through the system.

I solved the whine in our E39 compressor by evacuating the system and recharging. The car cooled perfect, you would never have thought. I even put 2 ounces of oil in the system before anything else. It barely helped with the noise. I evacuated it and weighed what I got out. It was at 60% of the factory charge. Put back in the exact charge amount, and no more noise.

Interestingly, this all came about by me losing A/C cooling in my prefacelift E38. I got all the tools and found out my car was at 50% of the factory charge when I weighed what I got out of it. I didn't have any compressor noises though. Maybe they changed the compressors post 1998?

[purplecty]

Whats the best way to do this? Im thinking someone with the big professional HVAC machine and not using those cheap cans from an auto parts store?

[Reflex]

Whats the best way to do this? Im thinking someone with the big professional HVAC machine and not using those cheap cans from an auto parts store?

Yeah better let a pro do it. Really not worth saving a few bucks. Not to mention that $30-40 can will be a waste at the end. They charge $70-80 here in Atlanta.

[SenorTips]

Thanks guys I will try relieving all the charge from the factory and recharging it again to full capacity.... I will also keep it updated thanks again BF

[Frankie]

A/C system check found leaking schrader valve on high-side (near condenser); evacuated system (only a little over 1 lb -- should be 1.5 lbs); 2 new valves installed; recharged. My system blows snow now, without the growling noise at idle. $265. Ready for summer!

[sealbeach740]

A/C system check found leaking schrader valve on high-side (near condenser); evacuated system (only a little over 1 lb -- should be 1.5 lbs); 2 new valves installed; recharged. My system blows snow now, without the growling noise at idle. $265. Ready for summer!

May I ask if you took your 7 to a BMW dealer or indy, or, did you take it to an A/C specialist to have the system check done/schrader valves replaced?
Thanks!

[Photoguy30523]

keep us posted i have the same sound.

[Frankie]

May I ask if you took your 7 to a BMW dealer or indy, or, did you take it to an A/C specialist...

Neither. I took it to a local corner auto repair shop (Midas [Muffler] Auto) -- any will do -- as it doesn't require specialized service.

[Lamer321]

I have that same noise in the video above. have an A/C system evacuation and recharge scheduled for tomorrow.

[Dan750iL]

I have the same noise and I am planning on having the system emptied and the refilled. Just won't happen for the next 3 months. This car is not leaving the garage for another 3 months.



-Messan

I have this same noise. I'll be looking forward to seeing how the refill works.

[Lamer321]

I have this same noise. I'll be looking forward to seeing how the refill works.

I will update as soon as i can

[sealbeach740]

Neither. I took it to a local corner auto repair shop (Midas [Muffler] Auto) -- any will do -- as it doesn't require specialized service.

Thanks for the info, Frankie.

[serious7series]

I have that same noise in my 2000 750. Ice cold AC, but noisy when the compressor is on (sounds like a whirring sound, as depicted in the youtube video). I plan of having system evacuated and recharged. Ill report back...

[01740ISP]

evacuated mine and had it refilled. Still does the noise at times but it is less noticeable
I have not driven the car the last few months so this is my impression from when I was getting back from the shop.
they could not find a leak in the system either even though it was low on freon. They added a dye for next time.
I hope it helps on yours.

-Messan

[racer2086]

No leak necessary. You slowly lose charge over a long period of time. Considering these cars are 15+ years old, that's long enough to need a recharge without having an obvious leak.

[serious7series]

I have that same noise in my 2000 750. Ice cold AC, but noisy when the compressor is on (sounds like a whirring sound, as depicted in the youtube video). I plan of having system evacuated and recharged. Ill report back...

Brought my 750 to a reputable indy AC shop. He first ran the AC at max and took the air temp coming out the main center face vents: 38 degrees F! He then tested the high and low pressure readings (both were within range @ 100psi and 28psi). He then added 1oz of oil to the AC system (PAG 100 is the correct oil, and the manual calls for a total of 6oz). Made no difference in that sound. He did not evac and refill, as he thought it wouldn't benefit anything.

I'm at a loss for making that noise go away.

[racer2086]

You cannot tell if the system is a little low or full based on the pressures. My 7 didn't start losing cooling ability until it was down to about 50% charge -- interestingly, no compressor noise. Now, even with the 540 at 60% charge, the pressures looked fine and car blew cold, BUT the noise was there.

Evacuating each car showed my 7 at 50% charge and the 5 at 60% charge. (This is by weighing the tank before and after evacuating and comparing the change against the charge weight on the A/C label). My car instantly started blowing at 28*F vent temp with the ambient around 75-80. The 5 was the same, but the compressor noise in the 5 stopped.

Long story short, you need to evacuate and recharge with the proper weight. If there is not enough refrigerant in the system, not enough oil gets circulated, since the oil circulates with the refrigerant. Your car is probably low, but you won't know it looking at the pressures. The only way to know is to weight it.

[SpeedyE38]

Is that the guibo?

If the air is cold, should not need a recharge. Not sure what groggy means but if it's gurgling, make sure it's draining on each side of the transmission. If it's more of a groan, could be the bearings on the fan motor.