BMW’s traditional Silky Six, the 6-cylinder NA N52 engine, is an engine that is quite durable.
From 2005 to 2013, it was widely used in the 1 Series, 3 Series, 5 Series, Z4, X Series, etc.
As a result of being used in so many models, the parts that will break down due to aging are roughly fixed.
If you perform preventive maintenance in advance and have spare parts on hand, you should be able to avoid sudden trouble while you’re out and about.
We’ll explain everything from serious trouble that can keep you from getting home, to the causes of engine malfunctions.
The part prices are OE part prices at FCP Euro.
Serious troubles that will prevent you from going home
- Alternator
- Battery
- Radiator hose, coolant hose
- Water pump & thermostat
- Oil filter housing
1 Alternator
The alternator, which is responsible for generating electricity, is not a particularly fragile part, but it can cause the amount of electricity generated to become unstable or overcharge due to deterioration over time.
If it gets bad, the engine may suddenly stop.
It also cuts off the power supply to the power steering pump, making the steering extremely heavy.
Be careful, as there may be warning signs such as errors in the IBS (intelligent battery sensor) or water pump.
The alternator is quite an expensive part to replace, but in many cases, it seems that the problem can be improved by replacing the voltage regulator, which costs about one-tenth the cost of the alternator itself. It can be done DIY.
Bosch regulator $40-, bolt kit $21-
By the way, my car had a problem where the alternator pulley came off while driving, damaging the tension pulley and belt. If you hear any strange noises, stop and check.
2 Battery
Although it is not strictly an engine part, the battery will last for 2-3 years.
If the engine won’t start, the lights are weak, the air conditioner doesn’t work, the wipers are slow, etc., it may be time to change the battery.
You can replace it yourself, but you will need to register the battery after replacing it, so you will need a compatible OBDII reader.
BMW’s battery is located in the trunk due to the weight distribution between the front and rear.
However, if you are jumping when the battery is dead, do not connect the jump cable directly to the battery.
This may destroy the electrical circuit and require unnecessary part replacement.
Always jump using the red terminal in the engine compartment and the body ground.
3 Radiator hose, coolant hose
If cooling water leaks from the radiator hose or coolant hose, it can cause the engine to stop.
There are three points you should pay particular attention to.
- The flange connecting the thermostat to the cylinder head
- The outlet from the upper radiator hose to the reserve tank
- The vent line returning to the reserve tank at the top of the radiator
In particular, 1 is made of plastic and will crumble under the heat of the engine, oil, and coolant, so it is best to replace it with an aftermarket metal part as soon as possible.
All can be replaced by DIY.
Radiator upper hose $30, coolant hose flange $25, vent line $30
4 Water pump & thermostat
The water pump and thermostat will break after about 100,000 km due to aging.
If they break, the car will not be able to be driven, so if you think it’s about time to replace them, we recommend replacing them as soon as possible.
You can replace them yourself, but you will need to work from underneath, so a floor jack and jack stands (horseback) are essential.
Water pump and thermostat $370 (bolts and coolant included)
5 Oil filter housing
The oil filter housing next to the cylinder head, oil leaks from here in particular need to be dealt with as soon as possible.
It can cause deterioration of the coolant hose flange mentioned above, and oil can adhere to the belt, causing serious damage to auxiliary equipment.
If you notice oil seeping, take action as soon as possible. You can replace it yourself.
Gasket $12-, Bolt $12-
Engine lumpy trouble
- Ignition coil & spark plug
- VANOS solenoid
- Camshaft position sensor
- Crankshaft position sensor
- PCV valve
6 Ignition coil & spark plug
If the engine is rumbling or you feel vibrations when waiting at traffic lights, the direct ignition coil of one of the cylinders may be defective. In this case, you need to replace the coil and plug.
It used to be made by BOSCH, but it has now been updated and it seems that Delphi coils and NGK spark plugs are good.
By the way, it is not good to mix BOSCH and Delphi coils. In this case, replace all cylinders with Burn. It can be replaced by DIY.
Coil + plug kit $240- (for 6 pieces)
7 VANOS solenoid
The VANOS solenoid on the front of the cylinder head is directly involved in controlling the valve lift amount, and if the VANOS solenoid malfunctions, the engine will rumble.
Simply remove the VANOS solenoid and clean it with a cleaner, but it would be even better if you could use a 9V battery to operate the solenoid and clean the dirt inside as well. This can be done DIY.
If you replace the part, the genuine one costs $201-
8 Camshaft position sensor
The camshaft position sensor is located near the VANOS solenoid. It is involved in controlling the ignition timing.
If it malfunctions, the engine will rumble.
This will be handled by replacing the part. It can be replaced DIY.
Sensor $52-
9 Crankshaft Position Sensor
The crankshaft position sensor is located at the bottom of the intake manifold. It also controls the ignition timing. If it malfunctions, the engine will rumble.
This can be done by replacing the part. It can be replaced by DIY, but it is located quite deep inside, so you need to completely remove the manifold or use a long extension to access it through the gap between the parts, which is difficult. (It’s mainly just the location that’s difficult.)
Sensor $73-
10 PCV Valve
In the old model, it’s located inside the manifold, and in the new model, it’s located behind the valve cover.
If it malfunctions, the engine will rumble.
This can be done by replacing the part. It can be replaced by DIY, but it’s located quite deep inside, so it’s quite difficult.
Problems that should be fixed if you have the chance
- Valve cover oil leak
- Oil pan oil leak
- Engine mount lifespan
11 Valve cover oil leak
This is caused by the aluminum bolts stretching.
If oil leaks into the plug hole, ignition failure will occur, so depending on the symptoms, immediate action is required.
It can be replaced at DIV, but it takes time because many bolts need to be replaced and torque management is also important.
Gasket kit $107-
12 Oil pan oil leak
This is also a chronic condition, just like the valve cover.
However, while it is possible to replace the gasket itself by DIY, it is necessary to remove the subframe to remove the oil pan, and DIY work is very difficult.
You will need a floor jack, jack stands, and an engine hanger (something to hang from above).
Gasket $35-, Bolt set $34-
13 Engine mount
The engine mount, which supports the engine from below at two points on the left and right, will deteriorate and become unusable after about 100,000 km.
It is possible to replace it yourself, but since it is a part replacement in a narrow, deep space, it is quite a difficult job.
Engine mount kit $170-