BMW F10 523i oil leak repair Rain leak prevention

Detailed explanation is available on YouTube!

BMW F10 523i

Arrived in stock for seasonal inspection.

Before switching to 4-cylinder turbo midway through the model

This is a model equipped with an inline 6-cylinder NA engine that was only available in the early days.

It's still very popular.

Please be advised that smoke comes out of the engine.

It is hanging from the head cover gasket.

One more place.

between the engine and the oil filter housing.

Both seem to have been replaced several years ago.

Why does the oil leak occur again?

I'll take it apart for now to find out the situation.

It came off.

This time we will replace the valve cover ASSY.

There are two reasons!

The first one.

The resin cover has cracks due to deterioration over time.

There are cases where this occurs.

The photo below is an example of this.

Even if you fix other oil leaks, oil leaks from cracks.

This will cause air to be sucked in secondarily, causing engine malfunction.


The red circle adjusts the pressure inside the crankcase.

This is a mechanism called crankcase ventilation.

The oil and air contained in the blow-by gas are roughly separated here.

・Oil is on the engine side

・Air is placed on the intake manifold side

There is a role to return.

This system also tends to become clogged over time.

Due to the air line being clogged, the gas has nowhere to go.

The pressure inside the crankcase increases rapidly.

This increases the pressure on the packing that tries to escape from the inside to the outside.

As a result, oil will gush out from the packing which can no longer withstand.

The gasket seems to have been replaced in the past, so it's still soft and elastic.

Normally, the gasket of a vehicle that leaks oil to this extent is

Most of the patterns deteriorate and harden over time.

Recurrence of oil leaks is caused by abnormal internal pressure in the crankcase.

The filter housing gasket is still soft as well.

In many cases, it hardens into hard pieces as shown in the photo below.

This is also thought to be caused by increased internal pressure.

Assemble while checking the tightening procedure.

Readjust Valvetronic etc.

Do a road test and make sure there are no abnormalities!

While working, we will also take measures to prevent rain leaks.

This vehicle is right-hand drive.

I have removed the cover of the problem area.

There is a hole on the passenger side that is closed with a yellow blind cover.

This is a service hole where the steering shaft for left-hand drive cars passes.

Over the years, dead leaves and dirt tend to flow into this area.

There are signs that water has already accumulated on this vehicle, forming a pond.

If the limit is exceeded, rainwater will flow into the car.

The steering ECU is located at the foot of the passenger seat.

If it gets submerged in water, it will be a big pain.

We will take measures!

Rain leaks can be prevented if water does not accumulate and form a pond.

Prevent damage by creating an escape route for dirt and rainwater.

F0X series F1X series

・5 series

・6 series

・7 series

Right-hand drive cars fall under this rain leak case.

Early measures are recommended.

Let's take a jab in advance against things that can be prevented.

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