[PizzaBoy_N52]

Just spoke with my mechanic trying to diagnose the oil-burning and rough idle issues. He said he found perfect compression but all of the spark plugs in the engine were completely oil soaked.

Ideas??

[Tambohamilton]

Valve stem seals?

Do you get blue smoke, particularly on startup?

To be honest, the n52 is mainly famous for oil control rings going bad. That would not affect your compression, but would allow oil to bypass the rings.

[PizzaBoy_N52]

Originally Posted by Tambohamilton

Valve stem seals?

Do you get blue smoke, particularly on startup?

To be honest, the n52 is mainly famous for oil control rings going bad. That would not affect your compression, but would allow oil to bypass the rings.

I noticed it happen a handful of times on both cold and warm starts. Its a very rare occurrence for me though...

[k90]

Originally Posted by PizzaBoy_N52

Just spoke with my mechanic trying to diagnose the oil-burning and rough idle issues. He said he found perfect compression but all of the spark plugs in the engine were completely oil soaked.

Ideas??

N52B25 ?

[PizzaBoy_N52]

Originally Posted by k90

N52B25 ?

I believe so, it's an 08 328i

[PizzaBoy_N52]

In the attached image you will see what my mechanic sent over as his diagnosis of my issues. Can anyone give me a second opinion?

[k90]

Your mechanic is saying that you have oil in your plugs - you have a valve cover leak. Rough idle is explained by oil. Your coils might be damaged by oil too.

Originally Posted by PizzaBoy_N52

I believe so, it's an 08 328i

That's 170kW N52B30.

How many miles? Service history?

Originally Posted by PizzaBoy_N52

In the attached image you will see what my mechanic sent over as his diagnosis of my issues. Can anyone give me a second opinion?

I believe N52B30 doesn't usually have valve stem seal problems unless engine has cooked and N52B25 has both severe oil control ring wear and valve stem seal leak problem.

Sort the valve cover seal and ignition first unless you are certain that the engine exhaust has oil in it.

EDIT: how much does it consume oil?
EDIT EDIT: oh there is oil in cylinder side of sparkplugs too.

[Suvorovo]

I'm only aware of the 06 N52B25 having piston ring problems. Can you take it to a second mechanic to confirm before spending 1000's on piston rings/valve stem seals. Did your mechanic use a camera to investigate cylinder walls? Could be high mileage oil chance intervals over the life of the vehicle.

Also, what exactly is "excessively wet"? Is it wet or not. How did the mechanic investigate the PCV/Crank Case pressure on the valve cover with the integrated PCV? From what I know, you can check PCV function by opening the oil cap. There should be a very small vacuum and a fast blublublub sounds on a functioning PCV system.

08 328i has the N52B30, SIM. I haven't seen anyone posting low compression on all cylinders before.

[k90]

Originally Posted by Suvorovo

I'm only aware of the 06 N52B25 having piston ring problems. Can you take it to a second mechanic to confirm before spending 1000's on piston rings/valve stem seals. Did your mechanic use a camera to investigate cylinder walls? Could be high mileage oil chance intervals over the life of the vehicle.

Also, what exactly is "excessively wet"? Is it wet or not. How did the mechanic investigate the PCV/Crank Case pressure on the valve cover with the integrated PCV? From what I know, you can check PCV function by opening the oil cap. There should be a very small vacuum and a fast blublublub sounds on a functioning PCV system.

08 328i has the N52B30, SIM. I haven't seen anyone posting low compression on all cylinders before.

+1 to PCV being still the most likelly suspect regardless. It's 90% of time PCV. Unless the car has been neglected and there has been excessive amount of carbon build up in oil.

Still waiting PizzaBoy_N52 to give details about oil service history and maybe how old the PCV valvecover is. I assume this is plastic valvecover with integrated PCV. It's has leaking seal so maybe not recent job.

Is 1000 dollars enough?

[PizzaBoy_N52]

Originally Posted by k90

+1 to PCV being still the most likelly suspect regardless. It's 90% of time PCV. Unless the car has been neglected and there has been excessive amount of carbon build up in oil.

Still waiting PizzaBoy_N52 to give details about oil service history and maybe how old the PCV valvecover is. I assume this is plastic valvecover with integrated PCV. It's has leaking seal so maybe not recent job.

I've been going through my stages of grief since the news

I recently replaced the valve cover at the advice of the dealer to fix the issues and it didn't fix the issue. There is not maintenance history to speak of, but judging by what the underside of the car looks like I can reasonably assume that the 2 people who owned this car before me took decent care of it.

What can I do on my end to get some more concrete evidence of PCV issues? I don't wanna keep paying mechanics to tell me the same thing over and over again.

[PizzaBoy_N52]

Something I noticed today: Car said it needed a quart of oil this morning. I poured one in and noticed the car drives significantly worse when I add a quart. Drives perfectly when it says it's down a quart. Are these sensors accurate enough to tell me if I overfilled?

[Suvorovo]

Originally Posted by PizzaBoy_N52

Something I noticed today: Car said it needed a quart of oil this morning. I poured one in and noticed the car drives significantly worse when I add a quart. Drives perfectly when it says it's down a quart. Are these sensors accurate enough to tell me if I overfilled?

If you have readings for low and high oil levels, your oil level/quality sensor is most likely working correctly. Did you drain 7 liter and fill 7 liter during your oil change? That's your best bet of measurement.

[PizzaBoy_N52]

Originally Posted by Suvorovo

If you have readings for low and high oil levels, your oil level/quality sensor is most likely working correctly. Did you drain 7 liter and fill 7 liter during your oil change? That's your best bet of measurement.

Last oil change was about 3 months ago, I typically change it every 4k miles. I do 7 quarts of Amsoil signature series 5w 30.

[k90]

Originally Posted by PizzaBoy_N52

I've been going through my stages of grief since the news

I recently replaced the valve cover at the advice of the dealer to fix the issues and it didn't fix the issue. There is not maintenance history to speak of, but judging by what the underside of the car looks like I can reasonably assume that the 2 people who owned this car before me took decent care of it.

What can I do on my end to get some more concrete evidence of PCV issues? I don't wanna keep paying mechanics to tell me the same thing over and over again.

When did you replace PCV/valvecover? What brand? What brand valve cover gasket and did you replace the bolts? It shouldn't leak out that soon unless the inferior gasket or bolts not replaced or correctly torqued.

Originally Posted by PizzaBoy_N52

Something I noticed today: Car said it needed a quart of oil this morning. I poured one in and noticed the car drives significantly worse when I add a quart. Drives perfectly when it says it's down a quart. Are these sensors accurate enough to tell me if I overfilled?

Sounds coincidental at first. But oil volume ofc displaces air volume inside the engine affecting pressures.

[PizzaBoy_N52]

Originally Posted by k90

Sounds coincidental at first. But oil volume ofc displaces air volume inside the engine affecting pressures.

I used an OEM valve cover I bought directly from the dealer, and this was done 1 month ago. Bolts and gasket were replaced as well and did come from the dealer.

[tcphoto]

I would go back in and doublecheck your work, it sounds like the gasket shifted when you put the cover back on or didn't torque correctly. I have the N54 and did the VCG 11/19 and know how that can happen.

[k90]

Originally Posted by PizzaBoy_N52

I used an OEM valve cover I bought directly from the dealer, and this was done 1 month ago. Bolts and gasket were replaced as well and did come from the dealer.

To be certain I need to ask if it has the plastic valve cover?
ADD: and if the spark plugs were changed so no oil residue in electrodes with new PCV is expected?

Originally Posted by tcphoto

I would go back in and doublecheck your work, it sounds like the gasket shifted when you put the cover back on or didn't torque correctly. I have the N54 and did the VCG 11/19 and know how that can happen.

But could that cause PCV to not work correctly?

[PizzaBoy_N52]

Originally Posted by k90

But could that cause PCV to not work correctly?

I didn't use a tourqe wrench when I did the job. The gasket still looks seated. I can see i have oil being pushed out of the oil cap. Seems odd to me. Is this an indication that I might have an issue of a pcv not opening?

I replaced plugs with NGKs 2 weeks ago.

[PizzaBoy_N52]

Originally Posted by k90

But could that cause PCV to not work correctly?

Yes plastic vc

[k90]

Originally Posted by PizzaBoy_N52

I didn't use a tourqe wrench when I did the job. The gasket still looks seated. I can see i have oil being pushed out of the oil cap. Seems odd to me. Is this an indication that I might have an issue of a pcv not opening?

I replaced plugs with NGKs 2 weeks ago.

All the aluminum bolts in the engine are yield bolts with specified jointing torque followed by angle. Won't work otherwise. There is no finger feel for these bolts. Unless you can do 7Nm by hand.

[PizzaBoy_N52]

Originally Posted by k90

All the aluminum bolts in the engine are yield bolts with specified jointing torque followed by angle. Won't work otherwise. There is no finger feel for these bolts. Unless you can do 7Nm by hand.

Regardless of weather or not they were tightened to spec, if the gasket isn't leaking then that can't be my issue can it?

[Suvorovo]

Oil coming out of the oil fill cap? Your mechanic said the pressure is good though. If you turned your valve cover upside down, some oil could have gone down and clogged the PCV. Usually people replace PCVs on plastic valve covers during gasket jobs.

There are also gaskets that go around the spark plug wells. Given what you just told us, maybe those weren't tightened or seated properly. Check the spark plug wells.

I'd redo the whole job and torque to spec

1. Replace valve cover and PCV. Can't guarantee your old valve cover wasn't damaged from over torqueing.
2. New Gasket and Bolt kit
3. Gear wrench makes a nice 30-200 inch pound torque wrench, please use at least a decent one. I use the gear wrench 30-250inch pound one. It's slightly cheaper.