[no maintenance mike]

first post here, looking to figure out and fix whats wrong with the 2008 328i i just bought.

1. I saw oil in various places over the engine so I took the cover off and I would like some input as to what im looking at because I frankly dont.

Ive got codes :
P0174 (lean condition, air leak bad gasket?)
P0174 (lean condition, air leak bad gasket?)
P1017 (bad eccentric shaft sensor)
P1017 (eccentric shaft sensor/seal leak?)
P0171 (likely air leak after MAF in boot, whistling noise symtom, possibly CCV valve failure)

Ive done some research already im looking for more opinions before I throw all the parts at it.


2. Also, i am looking for some help on parts ID and oil residue in other places.

[no maintenance mike]

The car has 99,000 miles.

It runs perfect except occasional rough idle and whistling noise once warmed up and idling.

Im also wondering, can someone tell me what these bad boys are? Thank you.

[Efthreeoh]

Steam clean the engine first to remove all the oil gunk. Then replace the valve cover gasket. That will include a new ESS gasket. The ESS failure code is probably just a dirty connector, but the ESS could be bad.

The whistle noise may be a clogged or bad oil separator in the valvecover, there are aftermarket replacements, or get a new valve cover. Inspect the valve cover closely for cracks.

Have you looked at the oil pan? It may be leaking now too by this time.

The power steering reservoir cap needs a new o-ring.

Now, you also have an issue with the serpentine belt. It is starting to slip off the tensioner. That means the bolt that holds the tensioner is starting to fail. Get a belt/tensioner kit and install.

At 100,000 miles, the maintenance schedule calls for a coolant change. While you have the coolant drained, replace the Mickey Mouse plastic flange with an aluminum replacement part (Google E90 "Mickey Mouse flange").

Lastly, the oil filter housing gasket looks like it is not leaking. That's good and bad because it most likely will leak eventually. So, the question is do you preemptively replace it now while the other maintenance is being done.

These all are common N52 problems at the 100,000 mile milestone.

[Efthreeoh]

This all means your engine is in great shape and once detailed with these maintenance items is good for another 200,000 miles of use.

[no maintenance mike]

Wow thank you for all the input!

1. How do you know the serpentine belt is going out

2. Is there anything else I should do while the valve cover is off besides ESS (Eccentric Shaft Sensor, right)?

3. Do you know what those two female plug looking things by the brake fluid resevoir are?

Ty

[Efthreeoh]

Originally Posted by no maintenance mike

Wow thank you for all the input!

1. How do you know the serpentine belt is going out

2. Is there anything else I should do while the valve cover is off besides ESS (Eccentric Shaft Sensor, right)?

3. Do you know what those two female plug looking things by the brake fluid resevoir are?

Ty

Look closely at the serpentine belt as it wraps around the main center pulley (that's the tensioner pulley). On your engine, the front edge of the belt is about a millimeter past the front edge of the pulley. That's the telltale sign the belt is starting to slowly walk off the pulley. You can tell from the grime on the engine there is a mist of oil moving around the engine bay in the air turbulence. The belt constantly moves and throws off most of the oil residue, but even a small amount of oil residue helps the belt eventually slip off the pulley. You've caught it early. The tensioner is probably still in good shape and it is just the aluminum tensioner bolt that is slowly and slightly bending, which un-squares the tensioner pulley from the plane of the belt running around the drive pulleys (AC compressor, PS pump, and alternator). I replaced my tensioner at 300,000 miles and it was still in good shape I've kept it as a spare). The tensioner/bolt/belt kit is now pretty inexpensive at this point, so replacing the tensioner is not much more of an extra cost. The Conti Kit (Continental brand) are OEM parts. I'd bet the belt is original and should be replaced at 100,000 miles per most belt manufacturers specs, so it is time to replace the belt anyway.

The two plugs are dummy plugs for the N52 that does not have DISA valves. The N52 in the 328i does not have DISA valves but does have the electrical harnesses for the DISA valves, so the plugs you see just hold the two DISA valve harness connectors in place so they just don't flop around under the intake manifold.

While the valve cover is off, check for broken headbolts in the front of the head near the cam drive sprockets. The heads of the headbolts can break. There are three (3) bolts all together, all on the front of the head, one of the bolts is outside of the valve cover under the oil temp sensor between the OFH and the head. IIRC the 2008 N52 does not have the issue; it was early production N52s. Also check for loose cam phaser bolts; they can back out and then get sheared off. If it happened already, you'd have a cam timing code. Just check the bolt heads on the cam phasers.

The best resource for parts identification is realoem.com https://www.realoem.com/bmw/enUS/select. The N52 has some detailed repair procedures that you can mostly find on the DIY subforum. But my advice is buy the E90 shop manual from Bentley Publishing. And buy a BMW scan tool (not just a generic OBDII reader). You need the BMW scan tool to reset BMW trouble codes and reset the Valvetronic motor when removing the valve cover.

Another thing you should do while you have the engine pulled a part is clean and swap the VANOS solenoids. If you do those, be careful and remove the attachment bolts first and put them on a workbench or in your toolbox. Then pull the solenoids out and clean them one at a time. Swap the clean one for the unclean one. Clean the 2nd solenoid then pop it back into the timing cover. THEN bring the bolts back over to the engine and thread them back into the head. You do not want to drop the solenoid bolts into the cam chain cover, so keep them away from the engine if the orifices for the solenoids are open. The N52 has no removeable cam chain cover, so you can't retrieve them.

Do not work on the 52 without reading the procedures (where you can find them online or in the Bentley service manual). You can f'up the engine quite easily if you are not familiar with it. Take your time. The N52 uses a lot of aluminum bolts on the engine block, so you have to pay attention to bolt torque specs. Get a small 3/8ths and 1/4-inch drive torque wrenches.

Lastly, the 2008 N52 calls for new sparkplugs at 100,000 miles. Looks like the coils have never been touched so I'd bet the sparkplugs are original and need replacement too.

[no maintenance mike]

You are the man! Thank you a ton Ill start looking into this stuff!

[Brandoch]

Why are you doing maintenance? You are doing wrong by your name.

[no maintenance mike]

Originally Posted by Brandoch

Why are you doing maintenance? You are doing wrong by your name.

Because poverty