Recommended Maintenance for the BMW E46 3 Series
Oil
Change your oil every 7500 miles even though the recommended interval is 15000 miles. This is not because the synthetic oil won’t last a long, but because the paper oil filters will disintegrate sending debris into your engine. I have always changed my oil with Mobil 1 5W-30 Synthetic Motor Oil
Air Filter
The air filter needs to be changed every 10k miles or 1 year. When choosing an air filter, make sure it is an OEM or of OEM standard air filter. Air filters that are not OEM can come with an oil sprayed on the filter designed to better trap contaminants. This is bad for these cars! It ruins the Mass Air Flow Sensor! A non-oil sprayed air filter that can be used is the Mann C3394 Air Filter
Spark Plugs
Change your spark plugs every 50k miles even though BMW recommends every 100k miles. Stick with the OEM plugs made by NGK. The part number is NGK (3199) BKR6EQUP
Fuel Filter
The fuel filter is a commonly overlooked part to replace. Every 40k-50k miles the fuel filter should be replaced. The fuel pressure regulator is also part of the fuel filter. There are many different brands of fuel filters for this cars, in the past, I have always used MAHLE Original KL 149 Fuel Filter
Differential Fluid
In a rear-drive, you have just one differential but in an XI you have 2 differentials and a transfer case that need to be serviced. Change this fluid every 30k miles, it is not lifetime fluid like BMW claims. In the differentials, a recommended fluid is Red Line 75W-90 Synthetic Gear Oil
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Transmission Fluid
Manual
More info soon…
Automatic
Change this fluid every 30k miles. This is not lifetime fluid either! Redline MTL is the preferred choice.
Power Steering Fluid
One of the easiest things to do is flush your power steering system with automatic transmission fluid (ATF), which is recommended every 50k miles. The best procedure is the Turkey Baster Technique to flush the fluid.
Coolant
Change your coolant every 2 years with BMW OEM Coolant
Water Pump
Do this prior to 100k miles and if you are still on the original one after 100k miles, don’t expect to be much longer. These OEM water pumps are made of plastic and love to break and spill your coolant out in seconds.
Serpentine Belts
Change your serpentine belts every 50k miles or if you visually see and cracking in the belt. This is a cheap and easy maintenance item, though can get a little tricky for Auto Tranny owners and the fan clutch. There part number for the water pump and power steering belt is Continental 6PK1538
