[lpaulodt]

Hi!

I am trying to support a friend with an issue in his E90 ‘08 325i N53.
There is a ticking / knocking sort of noise that seems to be coming from the the engine, not sure exactly where.
It is engine speed dependent and sort of random, sometimes it goes away, but it’s most of the time there.

As an effort to fix it, a few things already inspected/replaced:

- Timing chain, replaced
- Valve lifters, replaced
- Vanos solenoids, taken apart, cleaned and mounted back
- oil change, some shavings found in the last oil change, not sure if metallic or not as he didn’t check with a magnet, but from the picture I’ve seen, they were golden ish colored

Does anyone in here has experienced such problem before? Any clues what could it be? What should we look for?

https://youtube.com/shorts/ucL-Xm2St1M?si=GWwmpOqpX2OGblnS

https://youtube.com/shorts/GxGLBhc-N...0VqINuRwBsHoM3

[NZE90]

Most likely rod bearing. I've seen it a few times now. You would need to remove the sump and connecting rod caps to inspect the bearing shells.

[Hotter]

Originally Posted by NZE90

Most likely rod bearing. I've seen it a few times now. You would need to remove the sump and connecting rod caps to inspect the bearing shells.

I though N51/N52/N53/N54/N55 don't have issues with rod bearings?

[lpaulodt]

Thanks for the hints!
Anything else before we pull down the sump and check the bearings?

[NZE90]

Originally Posted by Hotter

I though N51/N52/N53/N54/N55 don't have issues with rod bearings?

Yes they do unfortunately, especially after changing the OFHG. Have seen it happen quite a few times

[NZE90]

Originally Posted by lpaulodt

Thanks for the hints!
Anything else before we pull down the sump and check the bearings?

Maybe pull the oil filter and cut it open to look for bearing particles.

[Hotter]

Originally Posted by NZE90

Yes they do unfortunately, especially after changing the OFHG. Have seen it happen quite a few times

Why changing OFHG has impact on this?

[NZE90]

Originally Posted by Hotter

Why changing OFHG has impact on this?

Nobody knows for sure. Google "rod bearing failure after OFHG change". There are shitloads of threads on various sites about it.

[ptpending]

n51 and n52 do not have this issue if serviced correctly
but sometime in US first owner do not change oil at all and car have 60000 mileage with one oil change
then all subsystems which depend on oil pressure start to work unstable
vanos
camshats and valves
chain tensioner
rod bearing oil starvation
n55 engine has additional factor for oil starvation due the introduced oil regulator
and then various noise can arise

[NZE90]

Originally Posted by ptpending

n51 and n52 do not have this issue if serviced correctly
but sometime in US first owner do not change oil at all and car have 60000 mileage with one oil change
then all subsystems which depend on oil pressure start to work unstable
vanos
camshats and valves
chain tensioner
rod bearing oil starvation
n55 engine has additional factor for oil starvation due the introduced oil regulator
and then various noise can arise

OP has N53 which has a different oil pump system to N51 N52 and also has the oil pressure control solenoid on the side of the block like the N55

[ptpending]

Originally Posted by NZE90

OP has N53 which has a different oil pump system to N51 N52 and also has the oil pressure control solenoid on the side of the block like the N55

i've checked parts catalog and EU 325i with N53 has same oil pump like mine N52 130i
but i agree that N53 has oil pressure regulator valve

[lowrydr310]

Could be rod knock, check the filter like the suggestion above and look for metal particles. You said golden-ish metal shavings in the oil last time you did a change? Yeah that might be it.

It could also be injectors or even a loose spark plug. N53 uses the piezo injectors like the N54, if they're not seated properly they could make noise like that, and oval the bore while doing so.

[0l0dom0l0]

Does it go away when you depress the clutch?