This means that, for easier working on the switch from below, it may be best to jack up the car, and support it on stands on the axle line. On petrol engines, the switch is attached at the front side of the cylinder block over the oil filter section whereas, on diesel engines, it can be mounted either at the front side of the cylinder block in the area of the oil filter housing or directly in the cylinder block near to the transmission end. First, remove the battery negative terminal, second, cut the wiring connector and remove from oil pressure switch. Depress the switch and unscrew it and get ready to find the sealing washer if it exists, expecting to find oil dripping. If the switch will be kept open for a long time, it is recommended to seal the hole to avoid loss of much oil. For refitting, check to see if the sealing washer is damaged to the point where it has to be replaced; if none is available, clean the switch and coat the threads with sealant. Wring the switch back tightly and connect the wires as before, if needed, lower the vehicle to the ground. Last but not the least, check the degree of the engine oil and add more if they are low.