[Isaac335d]

Hey all, I have a 2011 335d with about 104k miles that has been a blast since I picked it up at just shy of 40k two years ago. Last night I had to run to the hardware store and while backing out of the garage I noticed a "blip" in the power steering as I turned the a/c (heat) on. I pulled back in the drive way and popped the hood and smelled what seemed like rubber and saw a little smoke coming from the main belt area (technical term). When I turned off the air all seemed fine. Figured the a/c clutch was going and would take it in to the shop.

Today I had plans to bring the car to a local indy shop (first time needing repair since the extended CPO ran out) and on the way got low coolant warning while coasting down the off ramp, power steering came and went a couple times, battery charge warning flashed, and when I stopped I had some steam/smoke coming from the motor. When I pulled over and shut the car off there was the obvious smell of coolant and I noticed the edge of the main belt seems to have wear.

Everything that happened today would make me think it is a failed water pump but the mixed issue from last night is strange. Any thoughts or ideas on the culprit? I drove about 30 miles today and since it was evening and I wouldn't make it to the shop before the closed I left it and figured I would deal with it in the morning. Wonder if I would be safe to drive it to the shop or if I need to have it towed.

[sp1tfire]

Nothing strange. Normally when the WP goes - your car will overheat and give you a warning to stop the car, yours should be fine. Very possible the belt started shredding and damaged some coolant line, and the smoke are just pieces of it around engine bay melting. Most likely one of the bearings seized and cause the belt to melt while it was working.
Don't drive it, safer to tow, if the belt started shredding - then it can snap front seal and get sucked into oil pan with possible fatal outcome for the engine, so either diy it or tow it.

90% that you alternator bearing seized and caused all that mess, most likely idler and tensioner pullies are due to be changed too, if weren't before.
Maybe it was just old belt?

[cm335d]

Hello Isaac335d, I have a 2011 335d that had the exact same scenario happen as you described above. I cut my belt off this morning to spin the components and everything spins freely. I did notice a small amount of up/down slop on the water pump pulley, but there was nothing grossly binding up.
Could you please let me know what your final diagnosis and fix was for your car? Much appreciated!

[Underground6t9]

Wow 60k miles driven in 2 years

[charlie fairmont]

Check out the harmonic balancer threads in the diesel subforum.

[cm335d]

Thanks Charlie, I'll check it out!

[cm335d]

Was definitely the harmonic balancer! Used an inspection mirror to look at it and saw a really nasty crack in the rubber. Got really lucky that this happened to fail while backing out of my driveway. Thanks again for pointing me in the right direction!

[charlie fairmont]

glad you were able to get it sorted!

[cm335d]

Here's what it looks like off of the car. Waiting for my new one to arrive this afternoon.
https://drive.google.com/file/d/0Bws...ew?usp=sharing