I have a 2002 Lincoln LS heating and cooling issue

replace the reservoir would be one way to stop it leaking
for the heater to stop working could be an air lock in the cooling system

I have a 2002 Lincoln LS and the air conditioning works up until it gets 95 degrees outside then it stops working and just blows hot air. Any suggestions on why this happens?

that car has a intake manifold leak you have to check your car in the morning look in the plastic fill reservoir and it should be you to the cold line that is the line on top the hot line is the lower one make sure it is up to the cold ligne stick something in there if you can not see it

there might air in the system so you will have to bleed it or remove the rad cover and let the car run for a bit the should be on in full

Under the hood is the Heater Control valve need replacing.

It sounds like the dual climate control valve. It is supposed to close the valves when the a/c is turned on, but they get stuck sometimes. I have already replaced 2.

What happens is the valves get stuck and the engine heat will blow over the cool air making it feel warm, even though the a/c is working fine.

If it started out on one side of the car cooling better than the other than you can almost bet this is the problem.

They will be called a heater control valve by most auto parts stores. I think the part is Motorcraft YG378.

Another way to make sure this is the problem is to find the dccv and clamp the two top black hoses with pliers or something and see if the car gets cooler. It will still not get cold but this will let you know if the dccv is the problem.

replace thermostat,and antifreeze, check your oil see if it looks milky wich would indecate water in the oil and the antifreeze check for oil.if there is water in the oil be sure to change that also unfortunetly for you cold winter is the worst time to over heat a engine .

thank you,
vijay (vote for me)

this problem is caused by a defective air temperature control blend door actuator motor, it is about center of dadsh in air ducting, it moves the door that diverts air for cold from ac or hot from heater, you must remove the dash to repace it, about a 15 hour job fotr a home mechanic with a factory repair manual, nearly imposs without one.

its probably the compressor cutoff switch cutting your compressor off at the wrong time and causing your ac to blow hot. that switch is under your hood right on top of the engine easy to get to. I hope that helps you out!

The problem is most likely a bad dual climate control valve. This component is located on the right side near the radiator under the hood. It will have several coolant hoses hooked to it and 2 silver cylinders protruding from it. You can clamp off the heater hoses at the heater core and see if both sides cool then and this will tell you that the valve is letting coolant thru when it shouldn't be.

This will narrow it down to either the valve or the control head inside the car,or wiring in between them. The only way to narrow it down further is if you have a scan tool that could access the climate control data. Have seen several of these valves cause this concern and have only seen one control head cause it.