While attending to fuel filters, it is very important to take safety measures into account, given that there are risks involved in working around gasoline. Make sure the area where you're going to perform the work is well ventilated and keep away from any sparks or open flames. In E30 models, the fuel filter can be found underneath the vehicle near the fuel pump; for M42818 engines, on left side front frame rail; and for M44819 and M52/S52 engines in E36 4-cylinder and 6-cylinder models respectively near transmission cross-member mountings bolts. Release pressure off of the fuel system before starting by removing protective dust cover if provided. Tighten off both inlet and outlet lines with a set of fuel line block-off clamps so as to avoid any leakage during loosening of the fuel lines. Place an empty container under where the filter sits to collect all dripping fuels. Start by unclamping filter mount prior to detaching input tubing then output pipe after taking out this part (filter). Replace it in such a way that its flow direction should be noted which should make it stay secure while ensuring no mistakes are made with regard to connecting hose pipes properly as well as tightening some clamps on top of them. After completing this stage, reconnect everything back following reversal process but ensure that there are no leakages when done.