[LukasL]

Hi. Today I was driving my e91 335d 2010 (M57) and then I turned it off for 5 minutes. When I started it, the battery icon was displayed and I lost the power steering. I turned of all lights and AC, restarted the car and it worked fine. But now when ever I turn the AC on the power steering goes out immediately, even if I’m driving. All belts looks fine. What could possibly cause this and what can I check? Randomly I’m thinking about the alternator or battery, but I haven’t had any signs on them being worn down.

Any advice?

[Master_Chase]

Sounds like your harmonic balancer has separated and when the AC is off the load is light enough that it can still turn the belt.

[LukasL]

Originally Posted by Master_Chase

Sounds like your harmonic balancer has separated and when the AC is off the load is light enough that it can still turn the belt.

Honestly sounds very reasonable, thank you. Should I just replace it or can it be reinstalled/repaired? How can I confirm it’s the issue before fixing or replacing it?

[LukasL]

Originally Posted by Master_Chase

Sounds like your harmonic balancer has separated and when the AC is off the load is light enough that it can still turn the belt.

I started the car without ac everything good. Then I turned ac on and saw how the outer part stopped spinning so you were very correct about the diagnostics. Thank you so much man!

[montr]

You should fix it ASAP, before you loose electrical power from the alternator.

[LukasL]

Originally Posted by montr

You should fix it ASAP, before you loose electrical power from the alternator.

Yeah I’m not moving the car until it’s fixed. Although when looking for new part there appears to be both 192mm and 170 outer diameter that “fits” weird enough. It’s hard to measure the original part, would you by any chance know the correct diameter?

Also, what brands is to recommend? Febi is good, but what about SWAG, TOPRAN or RIDEX? They are a bit cheaper than Febi.

[Master_Chase]

My dad put a fluidamper on his if you go that route make sure you swap the alternator pulley wheel to a clutch pulley wheel.

[335dlci]

Whitbread is the way to go.

[MidWillamette335d]

Originally Posted by 335dlci

Whitbread is the way to go.

+1 on Whitbread, very happy with mine. It appears to be an upgraded OEM style with the rubber and fluid, plus he warranties it for life...