[Tjcf14]

BMW has released a Technical Service Bulletin – SIB 64 01 14 for Heating and Air-conditioning for the 335i / 435i with N55 engine.

Bulletin states that there is an intermittent whirring noise from the IHKA system when the engine is under load between 2,000 and 3,000 rpm, and sometimes higher RPMs.

Cause has been identified by BMWNA as vibrations coming from the A/C low-pressure hose, which are resonating into the heating and air conditioning system. (In my 335, this resonance could be heard in the cabin, and felt in the steering column.) The resonance will rattle/buzz whatever is loose in the dash.

BMW has developed a new mass weight kit to dampen vibrations in the A/C low pressure hose, being transmitted from the engine.

After experiencing this problem from the second week of owning my new F30, I had this kit installed today. Problem first manifested itself at about 200 miles, today I have over 4500 miles. When I applied moderate load to the engine in gears 1 to 4, there would be an unmistakable engine vibration right around 2500 RPM. My experience matches many of the videos posted by other Bimmerpost members.

My dealer was earnest in attempting to isolate the problem. First repair attempt, they initially found an engine cover loose. Second repair attempt they insulated the plastic engine cowling, nav screen, AC hoses, etc. Felt tape / wrapping was applied in multiple locations. 3rd attempt, after driving the car without the dash, and still hearing the noise, they isolated the problem to the AC hose. I can’t say enough about the terrific service efforts at the dealership. They worked tirelessly, including researching the problem from the various Bimmerpost threads I sent them. After communicating with their regional BMW reps, they were told a service bulletin was coming.

Bulletin was released this week, part ordered Monday, delivered Thursday, and installed today. Am very hopeful this will do the trick and I’ll finally be rattle/vibration/whirring noise free. Highlighted circle in the picture below shows the new kit installed on the A/C hose.

Drove the car about 15 miles today. The vibration/buzzing/whirring sound are definitely better – but need more drive time to fully determine if this new mass weight kit has cured all ills.

[BavarianFanatic]

Thanks for posting!

[Steven1077]

The fix is under the hood? That looks like an easy fix, my 435i will be built soon so I'm hoping they added this fix from the factory.
Thanks for the info, I'm sure that will save a lot of searching for others who have this problem getting it fixed.

[TheHitchhiker]

That is great news. I have the issue but wasn't able to replicate it at the dealer. However now I know how to replicate it and will take it there soon. So they can apply the fix! Keep us posted if it comes back!

[howiegu]

Many thanks for sharing.
I had it for year an a half, kind got used to it, now I know what to ask at the dealership.

[The Nerd]

So this isn't the same thing as the "electrical" sounding buzz that can be heard when accelerating slowly with the radio off (has to be very quiet to hear it)? Almost sounds like electrical interference or something. Not the same?

[BavarianFanatic]

Originally Posted by The Nerd

So this isn't the same thing as the "electrical" sounding buzz that can be heard when accelerating slowly with the radio off (has to be very quiet to hear it)? Almost sounds like electrical interference or something. Not the same?

I think it's the same thing.

[gomichaelkgo]

Wow, I got rid of an F30 335 because of this. Now, my new one does it too, but not as bad. If like to wait a bit to see if this works for you all before I take mine into the dealer.

I'm going to zip tie some heavy things to my hose to see if it helps...

[joonix214]

Wow, this is great news. Keep us updated in whether the rattle creeps up again. I was having this issue as well. Hopefully, this completely fixes the issue.

[Coolhydro]

Great find! Is there a ID or Number for this Service Bulletin?

[dmk11]

What's interesting is that this hose already has weight attached 5-10 inches upstream. It's hard to believe that rubber hose would cause this noise. What's the connection between low pressure ac hose and engine under load at 2500 rpm.

[claykin]

What is the plastic shroud I have circled in yellow? My 2014 335i does not have this shroud. I can see wires. connectors etc. where you have a shroud.

My neighbors 2013 is same as mine. Maybe BMW added after July 2013 builds?

[Glassy]

Thank you for the info! Please keep us updated!!

[m7ammed]

Please keep us posted if you can get a PDF version of the SIB it would be great so I can give it to my dealer in Saudi to fix the issue

[Tjcf14]

Originally Posted by m7ammed

Please keep us posted if you can get a PDF version of the SIB it would be great so I can give it to my dealer in Saudi to fix the issue

Dealership would not provide a hard copy for me to keep. My initial post has the bulletin number. Your dealer should be able to look up.

[BMW30_BLACK]

Does this refer only to 335 ? how about 320i ?

[jtuds]

So this is not the howling/whirring noise that some of us hear when we have our heat/AC fan on?

[Tjcf14]

Originally Posted by BMW30_BLACK

Does this refer only to 335 ? how about 320i ?

My understanding is that this is only for N55 engine.

[fecurtis]

This is certainly good to know. Thanks for informing the rest of us.

[Tjcf14]

Originally Posted by jtuds

So this is not the howling/whirring noise that some of us hear when we have our heat/AC fan on?

If whirring noise from AC occurs when idling I'd say no. The sound many of us have is a buzzing with moderate engine load.

[ft1330]

Holy crap thanks for posting. Through my testing I knew it was AC related as I've posted many times before. I thought it was a vent but apparently it was a hose. Still doubtful it is that but I can't wait to go to the dealership.

[ft1330]

Originally Posted by claykin

What is the plastic shroud I have circled in yellow? My 2014 335i does not have this shroud. I can see wires. connectors etc. where you have a shroud.

My neighbors 2013 is same as mine. Maybe BMW added after July 2013 builds?

I was wondering too. August 2013 build and no cover for me. Is it what the hose is supposedly vibrating against?