Procedure#

Step 1: Obtain Gaskets#

It is advisable to purchase gaskets directly from the dealer as the cheap copies you see online tend to wear far quicker due to poor manufacturing techniques.

For the N53B30A we are looking at part numbers:

  • 11428637821 for the Oil Filter Housing Gasket
  • 11428637820 for the Oil Cooler Housing Gasket

Step 2: Drain Fluids#

As we will be interfering with the coolant and oil loops, it is best to drain the car beforehand to prevent making a mess and losing fluids.

STEP 2a: Remove the undertray#

STEP 2b: Unscrew the Radiator Drain Plug#

Beneath the radiator on the right hand side is a small blue plastic screw that sits flush with the bottom of the radiator. That is the drain plug for the radiator. To unscrew it, I used the end of a small round spanner; a 10p coin will also do the trick.

STEP 2c: Undo Oil Fill & Oil Filter Cap#

Using an oil filter cap tool, remove the oil filter cap and oil filter as well as the oil fill cap. The oil filter along with the two o-rings from the cap can be disposed of.

STEP 2d: Unscrew the Oil Drain Plug and Drain Oil#

Beneath the car the sump will have a bolt, unscrew this and dispose of the copper crush washer. Allow the engine oil to drain.

STEP 3: Remove Airbox#

STEP 3a: Undo Bolts#

Undo the two 10mm bolts on the far right hand side of the airbox.

STEP 3b: Unplug MAF Sensor#

Unplug the cable going in to the airbox from behind.

STEP 3c: Loosen Jubilee Clip on Intake Boot#

Loosen the jubilee clip using a 6mm socket or wrench.

STEP 3d: Remove Airbox#

It may need some persuasion and a bit of wiggling but it should come free.

STEP 4: Remove Intake Guide#

The intake air guide is only held on by two T20 Torx screws from the front.

STEP 5: Remove Oil Cooler Housing#

STEP 5a: Remove Oil Cooler Hose#

Loosen the jubilee clip with a 6mm socket or wrench and carefully remove the hose, these hoses are prone to splitting.

STEP 5b: Remove Oil Cooler Housing Bolts#

There are three 10mm bolts that need to be unscrewed, two are above and visible, one is beneath. They are arranged in a scalene triangle pattern with the bottom bolt skewed to the left.

STEP 5c: Remove Oil Cooler#

This should just pop off, if it does not come off easily, pry gently from above.

STEP 6: Remove Oil Filter Housing#

STEP 6a: Unplug Oil Pressure Sensor#

Remove the sensor by pushing down on the metal clip on the connector located next to the oil filter cap.

(can be seen in the picture appended to Step 6b)

STEP 6b: Remove Oil Filter Coolant Hose#

Pry up on the wire clip and gently pull the hose off. They can be brittle so be careful during removal.

STEP 6c: Remove Mickey Mouse Flange#

There are two 10mm bolts that hold the flange on, removed those and gently remove the flange, this part is notorious for being brittle and breaking.

STEP 6d: Undo Oil Filter Housing Bolts#

There are three E10 bolts that hold on the Oil Filter Housing. They are located at:

  • Top of housing
  • Pointing towards Mickey Mouse Flange
  • Underneath front most bolt of intake manifold

Gently remove the oil filter housing, pry carefully if needed.

STEP 7 (Optional): Clean OCH & OFH#

This makes it easier to identify a new leak.

STEP 8: Replace Gaskets#

Remove the old gaskets and set the new gaskets.

STEP 9: Rebuild#

Repeat these steps in reverse order till Step 3.

STEP 10: Engine Oil Refill#

Step 10a: Drain Plug#

Put the new crush washer on the bolt and torque to 25nm.

Step 10b: Cap Gaskets#

Put the new o-rings on the cap, ensure they are in the correct place and are not pinched when the cap is screwed back on.

Step 10c: Refill#

Fill the engine with a maximum of 6.5 Litres of engine oil (5w-30 / 5w-40).

STEP 11: Coolant Refill#

Step 11a: Drain Plug#

Screw the blue drain plug back in until it is hand tight.

Step 11b: Refill#

Fill the engine with coolant until the bob reaches maximum height. The coolant level will go down after its first drive, be sure to top it off once the engine is cool.