cgy

Hello Everyone,

I have 2006 530xi and i had error about battery and realize that it is related with alternator.

I opened the hood and see oil leaking from oil filter cap (oil and oil filter replaced 2-3 weeks ago) and the serpentine belt pop out and still look good condition.

I just want to listen your comments about my solution path ways

1-Oil filter cap wrenched with torque again (If it has enough torque value, needs to replace cap and seal).

2-Re-assemble serpentine belt and adjust tension (i am not sure that do i need to replace tension pulley or not & do i need new belt).

While replace or re-assemble belt, do i need clean and rinse pulleys for to be in the safe side? Because those pulleys and belt would be oily now.

twh

What exactly happened with the serpentine belt? Did it come off with the engine running? Is it completely intact?

I would not drive the car nor turn it on until you do a couple things. This is not an overreaction!

There is an often fatal problem that can occur when the serpentine belt comes off with the engine running. Often times this is due to a serpentine belt fouled by oil from the valve cover, oil filter housing or oil cooler. What happens is that the space between the crankshaft pulley and the engine block is very small. The belt comes off, gets wedged into that too small space, the engine continues to run. the belt shreds and then pieces wrap around the crankshaft on the outside of the engine. Now these pieces are still getting wrapped and the engine is running and the belt shards are pulled into the engine though the front main seal. Inside the engine there will be belt pieces all in the timing section and oil pan and oil pickup. It is a real mess and will take a lot of work to clean out and even then you may not have gotten it all. Look for threads here and on bimmerfest.com. This failure mode affects the N52 and N54 engines.

So, if the belt is fully intact, you were lucky...

Fix the original oil leak source.
If oil was leaking out of the oil filter cap, you pinched the o-ring when reassembling or put the o-ring in the wrong space on the cap or the cap is cracked.
Clean up all the grime and oil on the front of the engine.
Clean off all the belt pulleys.
Replace the serpentine belt with a brand new one. The belt tensioner is not adjustable. I have replaced mine twice since new in 2005.

I replace my belt every couple years no matter.

cgy

Thanks for detail explanation. Yes the belt was come out and it was not shreded.

Do you think that i needed to replace tensioner pulley too?

Also do you have any advise for easy oil cleaning?

twh

I have the exact same car. Bought it new.

Yes, I'd change the tensioner and belt. This kit has what you need:
ContiTech ADK0022P -- Rockauto has for $112

I have twice used Original Gunk to clean off the front of the engine. This may be more than you need or maybe not. If you do use this, cover the A/C compressor and alternator and anything else with a bearing with some plastic so the Gunk cannot get to the bearings. Do it outside in the alley or somewhere you can make a smelly mess. Original Gunk is mostly diesel fuel and kerosene and it melts the caked on grease and grime like butter. What I do its cover all those things, take off the serpentine belt, spray the gunk, start the car (with the belt off), and hose everything down liberally with a garden hose. I don't use a blast spray, but a more gentle spray. I do this the whole time the car is running so if I got water where is should be the engine might tell me right away. Let the dry off with the engine running for a few minutes. It will smell of diesel and kerosene. Now take off the old tensioner and other parts that came with the tensioner kit. Put them all back on along with the new belt. Erase the OBD codes complaining about the alternator, which is to be expected since the belt was off.

If you engine is not that bad, just do some spot cleaning with red can CRC brake cleaner. The green can stuff is much less effective. I buy them at Walmart or Amazon for a lot cheaper than the auto parts store. Outlawed in some states I think.

You need a torque wrench or you cannot properly attach the aluminum bolts.

The aluminum bolts cannot be used or they may break now or while in use. Most or all of them are what they call a torque to yield bolt. One time use, the bolt actually stretches out during the tightening process.

Find and use the right torque settings...super important for anything aluminum.

Idler pulley is 40Nm...it bolts into some steel of the alternator.

Tensioner pulley long aluminum bolt is 25Nm and then 90 degrees more.

If the oil filter housing gasket or the oil cooler gaskets are leaking, change them both before you do any of this. To get at the oil filter hosing gasket, you will need a Torx E10 1/4" drive socket and some swivels and extensions or remove the intake manifold. A 3/8" drive Torx E10 will not fit in the area you need to get to.

Dj530

The belt should be replaced if it got contaminated with oil. Like you stated, the rest of the pulleys should be sprayed and cleaned off. Use Gates brand or something other than Continental, they tend to shred and come apart easier, also don't like being exposed to oil.
The oil filter cap should be inspected for cracks. Clean and install if okay and use a Viton O ring instead of the rubber one that comes with the oil filter kit.

cgy

Update and new Question

I cleaned pulleys and put back new belt in. I ordered new oil filter cap and installed. All is working good now but in that photo, tensioner pulley has little gap with belt. Is it normal or would it cause again belt loose? I controlled other pulleys all good with threads.