[otb234]

Just picked up a 330i Touring and the previous owner said it has needed topping up with oil occasionally. The oil cooler/filter gasket seems to be weeping but wouldn't be loosing enough to warrant a top up. Ill get it done anyhow.

Where else would there be to look? The rocker cover gasket looks fine, and the car doesn't leak any oil when sat at all.

Or is this normal?

[Phil325i]

Unless it's burning oil internally, the other possibility might be sump gasket.

[otb234]

How would you tell/check?

[Brian86]

Some oil consumption is normal.

I have an '06 n52 with 320k miles. It drinks a quart about every 3,500 miles. Some leaks out of the pan gasket, the rest is burning either via valve seals or rings.

Mine is probably a best case scenario at that age.

Check out the PCV system. It can be a source of considerable oil consumption. If you're lucky and have an early one the oil separator is external. Later models had it integrated into the valve cover.

[jericho_17]

My 06 330i consumes 0.5quarts between oil changes, for me is every 5,000 miles

[tcphoto]

It is time to clean the engine and observe where the oil is coming from. If you ignore the OFHG, it will eventually get on the drive belt and go downhill from there. Pull the belly pan and see where or if the oil is accumulating, there will be clues. It could be OFHG, OPG, Rear main seal or something else. Do you get an oil spot on the driveway when parked? Perhaps slide a large piece of cardboard under the car at night to see if it drips.

[smatanovic]

Originally Posted by otb234

Just picked up a 330i Touring and the previous owner said it has needed topping up with oil occasionally. The oil cooler/filter gasket seems to be weeping but wouldn't be loosing enough to warrant a top up. Ill get it done anyhow.

Where else would there be to look? The rocker cover gasket looks fine, and the car doesn't leak any oil when sat at all.

Or is this normal?

Check the oil filter housing gasket and valvetronic eccentric shaft actuator gasket. The former you can check simply by looking at the base of the housing: if there is oil/gunk on the outside of the housing, you have a leak. I would repair this one asap, since, as @tcphoto said, it can cause catastrophic engine failure. The latter tends to leak oil down the outside of the block; you can check for pooled oil between the spark plugs and ignition coils.

[Suvorovo]

As Brian said, check the function of the PCV system. You can open the oil fil cap while the car is running to see if a blown valve causes a big vacuum in the engine. A bad PCV system is a fairly common failure point on these engines and will throw a good amount of oil into the intake manifold. Overtime, the pressure buildup can cause you to have a leaking valve cover. Also, if the car was driven for short periods of time, the PCV heaters don't have enough time to do their job and oil gunk can clog up the pipes and PCV valve.

The n52b30 doesn't have a history of bad piston rings or some heavy internal wear that causes your oil consumption. The engine runs pretty hot and it will consume a little oil as part of normal function.

[StradaRedlands]

Originally Posted by smatanovic

-snip - you can check for pooled oil between the spark plugs and ignition coils.

That's where I had my unexpected leak. Only found it as it fouled the #6 coil & plug. Reminds me that I should check it again...

[Efthreeoh]

OP, so the fist step is record on paper or in your phone the amount of miles/kilometers the travels before the CBS issues the +1Liter notification. Once you have that data, you then can make a determination of how much oil the engine loses over time and mileage. No engine unless it has a hole in it really loses a lot of oil by leaking it. Oil loss is mostly caused by internal consumption of the oil through the combustion process and a result of component wear; as most have stated through rings, valve guides or the CCV system. IIRC BMW's spec is 1L per 1KM, so any loss better than that is not an issue to be concerned over. My 400,000+ mile N52 uses a liter about every 3,000 miles and the engine still runs like a scalded dog and has for years now.