4. 2 pre cat, 2 post.
Theres four o2 sensors in this particular bmw. Two before and two after the cat converters.
4
there are 2 pre and two after
Some 323 bmw's in the E36 platform only have 2 O2 Sensors, 1 pre cat and 1 post cat, unlike other BMW's that actually have 2 on the exhaust manifolds (1 per manifold) and two sensors at the cat for a total of 4 sensors. This might be a bit confusing but BMW went with a simpler design on the 323 E36 I don't know why.
On the exhaust pipe 1 before the cat and 1 after
The O2 sensor is in the exhaust pipe before the catalytic converter.
The rear oxygen sensors are located after the catalytic converter's Usually under the vehicles floorboard.
Many ppl might say 4 but in reality there are only 2 and it's about $100 a piece if u want to replace them.
Answerif you are referring to lambda emissions sensors then these are usually in the exhaust pipe, usually in the catalyst, if you are referring to oxygen volume sensors then these are often in the inlet manifold, but this is dependant on the vehicle.supply some more into and id be glad to help.Adamski(adam.francis@snowsgroup.co.uk)its the heated oxygen sensor bank2 sensor1
4, one per wheel
Many newer cars have sensor towards the dash board which you can turn on and off. Some cars have sensors in the front on new bmw cars.
A 1998 BMW 740il requires 8 quarts of engine oil.