You can check to make sure the radiator fluid is up to the correct fill level. Also be sure that the coolant/water mix is within the suitable ratio parameters. There is an inexpensive tester at all reputable autopart stores for that. You can also check to see if your thermostat is functioning properly. If it is not then your heat may only get slightly warm and may not heat up at all. Sounds like a thermostat.
You need to start out by checking the a/c-heater controller and the a/c-heater doors behind the dash for proper operation..............
Replace the heater core under the dash board. Fairly easy job if no A/C. But first before you start this, see if is there a coolant leak inside the cab? Usually onto the floor mat and/or what appears to be vapor exiting defrost windshield vent (leaves greasy like film on glass. If above is not happening then check thermostat for proper operation and heater hose connections for leaks. Heater cores are usually no more than $40-50. You should be able to buy at after market auto supply store.
the proper place for a heater would be under a window or where the area is cold.
the flap on the vent and defroster is stuck somewhere in between so it is not letting proper airflow to where you designate it possibly something sticky has fell down through the defrost vent and is constricting max. airflow
If it has the vacumm operated climate control check for a vacumm leak under the dash. Also check for proper operation of the vacumm valves operating the doors. Usually if the system breaks the control will default to the defrost position and vacumm leaks are a common cause.
If the thermostat is stuck wide open (and thus needing replacement) the engine will never achieve proper operating temperature and thus will not heat the interior of the car much.
I see a multiplication operation with a proper conversion factor
Check the radiator/condensor fan for proper operation.Check the radiator/condensor fan for proper operation.
Unfortunately, the easiest way to change the hose (firewall connections) is from under the car. If your Achieva has the dual hose with the black valve across both lines, make sure you go to the dealer for the replacement. It's important for proper operation. Replacing with regular heater hose will cause problems down the road.
lack of proper care. lack of proper (distilled) water in the radiator.
any thing that interferes with the proper operation of the nasal cavity.
Yes, that is a perfectly valid mathematical operation.