[E91 Hoarder]

Swapping the engine in 2006 325i.
What to change while I have the full access to the engine bay?

Here is what I can think so far:
- valve cover gasket
- oil pan gasket
- oil filer housing gasket
- replace water pump and thermostat
- replace O2 sensors
- spark plugs, coils
- inspect/replace rubber and plastic tubes. Any particular?

Anything else to consider?

[Suvorovo]

If you're swapping an unknown engine, the N52B25 has piston ring issues. Might be worth replacing those with the engine out and have a piece of mind.

Also,

PCV system
Vanos Solenoids - Could do without replacing if you know they work fine.
2 Oil Check Valves
Knock Sensors - Under manifold, harder to get to.
Eccentric Shaft Sensor - Under valve cover so why not.
Engine Mounts
Rear and Front main seals - buy the correct lubricant for the grooves on the seal. Very important.
Buy all the bolts

[E91 Hoarder]

Originally Posted by Suvorovo

If you're swapping an unknown engine, the N52B25 has piston ring issues. Might be worth replacing those with the engine out and have a piece of mind.

Also,

PCV system
Vanos Solenoids - Could do without replacing if you know they work fine.
2 Oil Check Valves
Knock Sensors - Under manifold, harder to get to.
Eccentric Shaft Sensor - Under valve cover so why not.
Engine Mounts
Rear and Front main seals - buy the correct lubricant for the grooves on the seal. Very important.
Buy all the bolts

Thank you!

More questions:

- If I am swapping in N52 from 328i, it, while the same engine, has different valve cover. Does it mean I need to swap the valve cover from my old engine?
- What else is different? somewhere I read that some sensors are different, but lost that post. Which sensors?
- Anything else needs to move over from the old engine?

[Suvorovo]

Do some research and see if the N52B25 ECU is compatible with a N52B30 (N52B25 & 2007+ N52B30 don't have DISA valve system). This might be your biggest issue unless you can get your hands on that 328i ECU. Most likely you cannot swap the valve covers. N52B25 is magnesium while the 328i is plastic and may have different bolt pattern. I have not encountered anyone doing this kind of change.

Additionally the PCV system on your N52B25 is built outside of the Valve cover with various lines running from valve cover, intake manifold, and oil pan. This is probably not compatible with a plastic valve cover of the 2007+ N52B30.

I believe eccentric shaft sensors are the same, look at the fitment on FCP euro.

https://www.fcpeuro.com/products/bmw...524879#fitment

Knock sensors are also same:

https://www.fcpeuro.com/products/bmw...566785#fitment

If you bought a 328i engine, buy parts specifically for the 328i.