Car struggling and overheating on an incline

I always park on a slight incline with engine cool...start with radiator cap off and air should travel to radiator and out

Over heating the engine is a serious concern. With the hood raised you should hear the motorized fan turn on just behind the radiator as the engine requires additional cooling.. If you look in from the rear of the radiator you should see the fan blades.

This electric powered motor operates on a thermostat and when the engine temperature rises this fan should come on. I'm assuming from your description that when driving and air is flowing through the radiator as the car travels the engine is nor overheating.

Check fan motor thermostat, check fan motor and check wiring.

Wiring Diagrams related to the Honda Civic
http://www.wiringdiagrams21.com/category/automotive/honda-automotive/civic

Motor engine cooling fan only runs as engine temperature requires additional cooling.

are you referring to the engine temperature overheating or the cabin temp not cooling down with the aircon on? I am struggling to think of a reason why operating the aircon would affect engine temperature

It means that the transmission oil is overheating and you need to cool the oil by allowing the engine to idle for a period of time . The transmission oil cooler is in the radiator and that means that the engine temperature will also be running hot . Check oil level in transmission and adjust to correct level. Check the load being carried /towed as this makes the transmission torque converter work harder and the speed you are travelling at What ever the reason I suggest that you run the fault codes to check for transmission problems

natural for engine temp to rise in Traffic - Until Themostat opens ) cooling fan sensor kicks on fan . But Antifreeze is not just a Cold weather item . Coolant is Absolutely Necessary for Hot Days . You must be full to recovery bottle setting of cold when checked prior to start up . Coolant for your make / model is Reddish - Pink colour and should have a reading of -25 thats negative 25 degrees the Lower the Better even - 50 .. Why ?? - 50 is 50 %% antifreeze / Coolant Concentrate MIX Gives Hot weather cooling Ability or very cold weather starting / winter HEAT .

sounds like your cooling fan isn't working at high speed the air will cool the engine but when your at low speeds there isn't enough air to do so so i would check your cooling fan that is more than likely your problem hope this helps.

it could be as simple as youre thermostat needs changing

Check your catalytic converter PRONTO! You may have a fire if it is getting that hot!

sometimes when an engine gets hot enough it will stop running due to the metal expansion when it is hot.if it cools off it will probably start but don`t run it very long especially without coolant.the thermostat may have seized in the closed position this sometimes happens as when the car is running the temperature flucuates the stat will close and open all the time(won`t close completely).another problem could be a bad head gasket that allowed coolant into the combustion chamber enough that the motor went into what is called hydraulic lock,coolant has filled the combustion chamber enough that the piston won`t move through out its normal travel.i would try changing the thermostat first refill cooling system and let run until the cooling fans have cycled on and off.if it doesn`t overheat and it cranks over when you try to start it then the stat is more than likely the problem.

If there was alot of debris, like you stated, it could have clogged the water pump. If you think about it, there really isn't all that much to a cooling system. Radiator, fan, thermostat, and water pump. These are the main components and by process of elimination, I would suspect the water pump. Hope this helps and best wishes.