Sick sounding M52B28 need help!
 

Hey guys, this year my car decided to bring me Christmas cheer by sounding terrible and having me worried all holiday... great.

At first I thought it would be the infamous VANOS seals. However, after listening to other videos online, it doesn't sound like what mine does. Maybe I'm using the stethoscope incorrectly?

Here is what it sounds like:





Oil level is fine and I added little more before the 2nd video to see if the noise changed, it didn't. The noise is not temperature dependant and changes with revs

Any advice?

-Skeo

Hmmmm... sounds like it might be crank related if it changes with revs. Either something is loose or its rubbing while the engine is running and causing damage. Could be the tensioner pulley, splined gear bearings, knock sensors? Just throwing out some ideas that maybe you might not have though about.

what happens when you rev it a bit? Does it speed up? Sound like it could be the idler pulley or something driven by the serpentine belt.

This is what I'm worried about. I'm not sure what I can do to isolate a particular area of the motor (head, crankcase, VANOS, etc.) so I know what to fix. Using the stethoscope indicates the noise is coming from the front of the motor, and it sounds like a spinning bearing. Though I'm not sure how to confirm.

As for the idler pulley, that might be the case, I will have to check those out. However, it sounds like it's coming from within the motor.

One more video with revs:

Actually it's starting to sound more like the AC compressor bearing.

See if you can put your hand on the compressor while the engine is running. (without touching the belt of course) If it feels like metal on metal 'grinding' then it's probably that. Another way is to disconnect the AC belt since it's separate from other accessories.

Happened to my dad's old RAM last year during summer. Man did it sound bad. I would check this as well. I know on the Mazdaspeed3, when the defrost is activated, the a/c belt spins once every few minutes which helps keep it from seizing over winter.

something sounds like its free wheeling.. or is it just me

Its a bearing from one of the accessories or pulleys.

Hey all, I have an update! It's sort of bittersweet, but heregoes:

It's definitely not something from the crank case or VANOS, which is great news. I pulled the belts off yesterday and ran the engine momentarily and there was no terrible noise. To verify it was a pulley, I spun them and they both made noise (both tensioning pulleys on the serpentine belt and the AC belt were shot). My car has no idler pulley, so that made things even cheaper! Hurrah.

So the mechanical tensioner and replacement pulley as well as new belts are on their way and should arrive next week. So I put the old belts back on since I still had to make a few trips from my place to Waterloo and back for the weekend. On the way back, shit hit the fan. Or should I say, the fan hit the rad.

Never before have I seen something fail so catastrophically. Turns out, the noise came from the water pump bearing and I couldn't hear it with the belts off and spun by hand. The bearing seem to have failed and the pulley became misaligned due to belt tension and sent the fan into the shroud, blowing two blades off in the process. My coolant is now all over the 401 (saves the coolant flush mess in my garage, at least).

Check this out:

Kind of an appropriate song on in the background (Another one bites the dust).

I will keep posting to this thread with updates. Looks like the rad may be OK and I'll just need a new water pump and fan. Anyone experience bits of metal in their cooling system? What method should I use to flush/get it out?

Edit: Before everyone harps on me for being silly and not suspecting the water pump, I did check for noise and I couldn't hear much. That plus the fact that the previous owner said he replaced it right before I bought the car (Sept. 2010) caused me to think it was OK. D'OH

Pump is now pulled. It has a metal impeller and is a BMW part. I have a feeling it's the original pump, so it makes sense that it blew up around now at 178,000km.

Here's how broken it is:


Next up is to replace the thermostat and housing while I'm there. I have an aluminium URO housing, but I've heard that people think they're crap. Any opinions?

Here's my "while I'm in there" parts list:
Belts
Mechanical tensioner and both tensioning pulleys
Water pump pulley
Thermostat
Thermostat housing
Water pump
Fan

Update:

Car is now fixed and the new water pump works well. Things that I've put in:

BMW composite water pump
Febi Water pump pulley
Behr fan clutch
BMW fan blades
Aluminium Thermostat housing
Whaler thermostat
New belts
New tensioning pulleys and tensioners

I am happy t works now. However, the new fan clutch is very stiff and the fan is pretty loud even at idle (and cold temperatures). It's a brand new Behr clutch, and it seems to be way too stiff. With revs, the car sounds like a Mac truck. Do the fan clutched have a break-in period?

Looks like a coolant system overhaul was overdue.

Glad you got it all sorted, should be good for the next couple of years.

identical happened to my 328is 2 months ago. But not only that, my waterpump plastic blades broke off.