Many blog readers are asking – what oil to use for their cars. In this entry – my opinion regarding this topic.
I will start with the simplest. I follow the recommendation of the manufacturer regarding the oil code. If 5W30 is intended for the engine – exactly that kind of oil I use for it. The argument “all gaskets of my engine are leaking, I gave to use a thicker oil” is not understandable to me. If the gaskets are leaking – they should be replaced. Exactly the same with increased oil consumption due to the worn-out piston group. The causes must be eliminated, not a thicker oil used!
In their modern petrol engines, BMW intends to use oils that correspond to the LL01/LL04 (LL – Long Life) certification. Yes, this certification makes sense because the oil with the appropriate viscosity of some shady manufacturers “drops” out of the list.
What brand do I recommend? I believe the oil of the “big three” – Liqui Molly, Mobil, Shell – would be a good choice. The BMW itself uses the oil of these manufacturers both for filling up new engines and the replacement in their dealer network services.
Should any additives be added? Only the ones intended for use by BMW AG. No other experiments!
Below are some, in my opinion, important recommendations related to oil exchange and the oiling of the engine.
One of the most important obstacles is the oil change interval. There is a lot of information on the internet forums, but my opinion:
a. when purchasing a new car, perform the first oil change after 1000 .. 2000 km, second – after 5000 .. 6000 km;
b. choose the next oil change interval 10.000 .. 15.000 km. If the car basically drives on the highway, you can choose an interval of 15.000 km. If the car is mostly used in city traffic, the max oil change interval is 10.000 km.
For my cars, I change the oil 2 times more often than indicated by CBS, which means around 15.000 km. The average speed of the car is 60 .. 65 km/h. So, I replace the oil after each 250 motor hours.
Let’s compare. If the average speed of the car is around 30 km/h (a typical value, if the vehicle is used 50/50 (city/highway), and you replace the oil as indicated in the CBS (around 30.000 km), the engine has worked 1000 motor hours.
Instead, if the average speed of the car is 15km/h (typically, if the car drives in the city), the engine during this interval has worked even for 2000 motor hours.
So – for my cars, I replace the oil 4 .. 8 times more often than it has been done for the vehicles with an average speed of 15 .. 30 km/h, and whose owners follow the CBS data. Waste of money or a good maintenance of the car – you decide!
The next significant aspect. Oil filter. I use only oil filters sold by the BMW Ag dealer network. It makes no sense to spare some EUR and “get caught” with a low-quality oil filter!
Third aspect. I don’t try to save by buying the oil “cheaper” or replacing it in “shady” workshops. Oil counterfeits are a huge industry! Dishonest service employees have an interest (financially) to “save”, using a chapter oil. In addition, such cheating can not be proved by anyone! Even more – such cheating will not even be felt initially by anyone!
Fourth aspect. When performing the maintenance, I evaluate the workability of the oiling system. For modern petrol engines, the oiling system, managed by DME, is used. I evaluate the performance of both the oil back valve and the performance of the solenoid. For 4-cylinder engines, I suggest checking the PWM values of the solenoid in idle and the driving conditions of max required pressure. The oil back valve ensures that the oil does not flow back into the oil pan for the switched-off engine, and the oil filter is fulfilled. It shortens the time necessary for the engine to pump the pressure in the oiling system. Instead, a clean and good working solenoid is critical for the system to have stable and correct oil pressure.