The question is somewhat vague, not knowing the make, model or year of the vehicle. That said, the most common ticking noise from the bottom of a vehicle is the fuel pump.. It is electric and usually located inside the gas tank.. It does in fact make a constant "ticking" noise when fuel pressure and volume is needed to run the engine. The pump is activated instantly when the ignition key is turned to the on position to build fuel pressure at the injectors for initial start.
Not enough info. Please reask question with year, make, model and engine size.
For what make and year of car?
A faulty crank sensor would make the engine not run.
If you mean for Coolant level sensor it is on the bottom of the plastic coolant dish on the passenger side of the car.
There is a sensor screwed into the bottom left of the radiator as you face the car.
Yes
The knock sensor retards the engine timing when there is a knock or ping detected. This will make the car a little sluggish. It is rare that the knock sensor goes bad.
A faulty oxygen sensor can make a car smell like gas. Oxygen and gasoline mixing wrong can cause excessive pollution. Replacing the oxygen sensor can correct this issue, and improve the gas mileage in the car.
varies by car, some cars do have it on the bottom, it just depends on the car and the way the engineers make for that car
the sensor is in the post behind the drivers door at the bottom , this sensor turns your headlights on in daylight mode when car is started but it is not the sensor that turns them on brighter ( or the dash lights ) automatically when dark
A malfunctioning oxygen sensor can cause the engine to be low on power.
if your car is driven by a cambelt not a chain then the sensor is located on the bottom pulley, when you pull this pulley out it will be there, its a bi black thick wire.