1. The engine coud have malfunchoned and 2. The car has to be broit to a Car Shop.
Under the motor
A junkyard or a Nissan dealership.
3.5 quarts.
on the front of the motor behind the fan
Directly on the bottom of the motor.
lack of oil
yes
Debris in the hoses or reservoir could cause the motor to overheat. Also, running the pump without fluid could do the same.
The blower motor speed resistor is probably burned out.
There are a lot of sites giving reviews of the Nissan Xterra. The reviews can be found on sites such as Edmunds, Auto Trader, The Car Connection and Motor Trend.
The thing that could cause a knocking noise in your car is the same thing that could cause it in all cars A rod that or a flat lifter. it all really depends on where the knock is if its higher and to the back of the motor, it could be a motor mount
could be the resistor on blower motor is bad