sounds like the water pump is bad. there are 2 holes on the water pump. top and bottom. when it goes bad water leaks out of either hole, usally the bottom hole. since it leaks, the radiator cant hold pressure and it over heats. the resivor is where the coolent would go if the coolent over heated and when the coolent cooled it would get sucked back out in to the radiator again. the radiator has to build up pressure to open the spring in the cap to cause that coolent to release. since there is no pressure the resivor will always stay the same.
Coolant is added to the plastic reservoir under the hood.
What type of coolant sensor? The below answer is for the coolant LEVEL sensor. The coolant TEMPERATURE sensor on my vehicle is located just next to the thermostat housing. On the front top center area of the engine just behind the radiator. Follow the coolant hoses if you have trouble. On my 1995 Jeep Grand Cherokee the sensor is located on the top of the plastic coolant reservoir tank. Look for a small (2-wire?) electrical connector.
Yes, there is a plastic cap that clips on.
It is on the clear colored plastic coolant reservoir
On the coolant reservoir. This is a plastic reservoir toward the back right of the engine compartment.
There is not a radiator cap, there is a coolant reservoir and it has a plastic cap that controls the pressure in the coolant circuit.
Most vehicles have a coolant reservoir (a clear plastic tub) with a phrase "engine coolant only" printed on the cap. This is where you should add engine coolant.
Its inside the coolant overflow tank/reservoir (its the plastic reservoir where you pour in your coolant). Look on the side (the side that faces the engine) and you'll see an electrical wire is connected by a harness. That's your coolant level sensor.
I use a cheap plastic turkey baster that I bought at wallmart and suck the contents out of the coolant reservoir ( it doesn't take as long to do as I thought it would )
The plastic coolant reservoir on the fender feeds directly into the coolant system. Just add coolant to the reservoir and if you have drained the coolant or otherwise emptied the system, you may need to check the level in the reservoir after running the engine, or more accurately, after the engine has cooled. Once the coolant level has stabilized, just check it periodically to make certain that the coolant level never gets too low.
You put it in the coolant reservoir, a plastic container with a radiator cap on it
If you are pouring it directly into the plastic antifreeze reservoir, it most likely has a crack in it.