Ford Focus A/C Troubles

It sounds like the engine rpm reflects the clutch cycling. When the vehicle is stopped, there is no air flow across the condenser, and that is where the cooling fans should be at high speed. Check to see if they are operational. When the ambient temperatures get to the extreme, the system is only going to provide so much comfort, and that will be compromised with no airflow. All you can do is make sure the cooling fans are functioning. It may be worthwile to have the system pressures checked, as well as the refrigerant level. If it is slightly low on refrigerant, the compressor cycle times, and overall performance can be degraded.

Yes it would be the fans either in front of, or behind the radiator. They can either push air, or pull air, depending upon where they are mounted. The water from the evaporator drain, is going to be based upon how cold the evaporator is getting, and how much condensation is being created. This could all be due to several factors, like charge weight, expansion device function, and the overall system performance. The airflow across the condenser is necessary to remove heat from the refrigerant, that it absorbed from flowing through the evaporator. Run the system, and feel the lines that you can access. One line(the smaller of the two) is what is known as the high pressure or discharge side, should be warm. The other larger line, known as low pressure side, should be cold, and may even build some condensation on it. Without knowning how much charge is in the system, and what the system pressures are when operating, it leaves a variable/unknown. The warmer the ambient temperature, the more negatively affected the system performance is going to be, because there is going to be less heat removed from the refrigerant at the condenser.

While there is nothing for me to answer. And while you wait on gstacy to return, I'll give you the Country Boy explanation on how A/C sorta works'

We'll use your house A/C as the model

One would think that the Fan in your house is blowing over some ice cold radiator thingee to make the house cold. The thingee inside is called an evaporator! Car too. The system is not makin' nothin' cold. It's absorbing the heat out of the air, from inside the house.

Its in a "gas state", inside the pipes, at the evaporator. This is the "absorber"!

This "Heat Bearing" gas now travels thru the pipes to outside. The radiator thingee outside is called a Condenser. In your car too!

The box outside has a fan in it. It cools the condenser coil, the gas has turned back into a liquid as its cooled in the condenser-hence its name! The cooled liquid now returns back into the house.

Just before the EVAPORATOR, it gets sprayed back into a gas

The cycle begins again!

Now lets go back outside to the condenser--Put your hand in the air the fan is blowing.

Know what that is?

That's the heat that was in your house. It's now being transferred outside!

Car is EXACTLY the same thing, just a bit more, technical terms, I've skipped over

If your condenser don't cool down, with air flow, Fan-generated or Traveling speed generated AIR. The liquid is not cooled enough!

Cannot turn back into gas when it should!

So here's what you need to check, as far as I can see, insure your system is properly charged. Wait. Wait. How can you properly charge it, if the mechanicals are not working right?

Make sure the condenser fins are clean, I use Purple Power, in a pump up sprayerWatch Your PAINT. Rinse everything well. Or use another recommend product, not so harsh!

Make sure your fans operate when they should!

Properly charge your system. WITH REAL GAUGES. The Auto parts store stuff is good. ONLY IF YOU KNOW WHAT YOU ARE DOING. This ain't EZ, like filling up your radiator! Would you let your sister, remove your appendix?

All yours gstacy!

The Medic