What happen when I remove out the thermostat?

Yes. You the car can drive as usual without thermostat but it will cause high fuel consumption.
Because when engine in cool temperature it will in rich mode (more fuel) to heat up. If without thermostat to cruising in highway the car will become high fuel consumption.

Under the thermostat housing mounted on the engine at the "engine side" of the upper radiator hose. That "usually" happens when the thermos is stuck open & the computer is getting cool readings from the anti freeze because its flowing too freely. More fuel is added due to bad temp readings. Drain some coolant, remove rad cap, remove thermos housing, Clean gasket or r/r O ring & replace thermostat. Reinstall. Refill cooling system, let it run.refill overflow bottle after warmed up. Ck for heat & leaks. Good luck

it could be you have an air lock in the cooling system
remove the rad cap from the rad, start the engine and let it run until the coolant drops (add to fill it back up) or until the coolant boils out of the rad spout.

maybe pull the heat sensor. -replace it OR clean it off, reinstall it.

Yes, the thermostat. I don't know exactly where yours is - but the thermostat is usually on the engine near a radiator hose. When cool, it stays closed to heat the coolant in the engine block and keeping hot coolant in the radiator to be cooled. Once the engine has heated the coolant to 185 ~ 200 degrees, the thermostat opens and allows the hot coolant from the engine to enter the radiator - which forces the colder coolant out and into the engine block - to keep it from over heating.

Your thermostat may be stuck - keeping it from opening / opening fully. You can test it be removing it and dropping it into a pot of boiling water on your stove - it should open in water that hot.

Do not work on the thermostat, radiator or coolant while the engine is hot. Opening the cooling system may result in spilling coolant and making a mess if you are unprepared for it.

You are correct in your suspicions.
The thermostat blocks flow thru the radiator to help the engine warm up. The coolant still flows thru the block with the thermostat closed. If you remove the thermostat the cooling system should flow thru the radiator and stay below 160 degrees if the air temp is below 90.
If the thermostat is out and the engine is getting hot at idle speed, either the water pump has failed, or there is another blockage in the engine block.

Check for collapsed radiator hose first.

Do the cooling fans come on? If not, check fuse, relay and if still no function- fan thermostat switch.

If fans do come on, replace water pump.

Removal & Installation 2.2L VIN 4 To Remove:

1. Drain the cooling system.
2. Remove the lower radiator hose from thermostat housing.
3. Remove the thermostat housing bolts and outlet.
4. Remove the thermostat.
5. Clean the mating surfaces.

To Install:

1. Install the thermostat.
2. Install the thermostat housing and bolts.
3. Install the coolant housing bolts. Tighten bolts to 14 Nm (10 ft. lbs.).
4. Install the lower radiator hose to thermostat housing.
5. Fill the cooling system.
6. Inspect for leaks.

2.2L VIN F To Remove:

1. Remove the exhaust manifold. If equipped with an automatic transmission.
2. Drain the cooling system.
3. Remove or disconnect the following:
   
   
   • Thermostat housing to water pump feed pipe bolts.
     
     
   • Thermostat housing to water pump feed pipe.
   • Thermostat.

To Install:

1. Install or connect the following:
   • Thermostat.
   • Thermostat housing to water pump feed pipe.
   • Thermostat housing to water pump feed pipe bolt. Tighten bolt to 10 Nm (18 in. lbs.).
   • Exhaust manifold. If equipped with an automatic transmission.
2. Fill the cooling system.

2.4L VIN T To Remove:

1. Drain the cooling system.
2. Remove the exhaust manifold heat shield bolts and shield.
   
   
   
   
3. Remove the coolant inlet housing bolts.
4. Lift vehicle.
5. Remove the coolant inlet housing stud from the oil pan.
6. Remove the wheel.
7. Remove the right engine splash shield.
8. Remove the transaxle-to-engine block brace bolts and brace.
9. Remove the radiator outlet pipe.
10. Remove the thermostat.
11. Clean the mating surfaces.

To Install:

1. Clean the mating surfaces.
2. Install the thermostat.
3. Install the radiator outlet pipe.
4. Install the transaxle-to-engine block brace and install bolts.
5. Install the right engine splash shield.
6. Install the wheel.
7. Lower the vehicle.
8. Install the exhaust manifold heat shield and bolt.
9. Tighten the exhaust manifold heat shield bolts to 14 Nm (10 ft. lbs.).
10. Fill the cooling system.
11. Inspect the system for leaks.

could also be that the water level in the radiator is too low.
if water is ok then it could well be as yo ustated, that the thermostat is stuck in the closed position. thus over heating the engine and not letting the hot water out into the cooling and cab heating system.
to test thermostat remove when engine is cold and put in a glass of boiling water and watch to see if it openes.
also try to run you car with the thermostat removed close the housing back up with a gasket fitted. and see if this resolves the problem you may have to choke the car a bit longer as it will take longer to warm up but it should be ok just for a test.

Warning: water cooling systems are under pressure when breaching a system ensure precausing are made not to get burned release the opening valve slowly with a rag over the valve to allow the pressure to release in a controlled way.

Removal
CAUTION: Do not mix Standard (green) Coolant with Extended Life Coolant (orange). If mixing occurs, drain engine cooling system and refill with originally equipped coolant type. If this contamination occurs the service change interval on Extended Life Coolant will be reduced from 6 years/150,000 miles to 3 years/30,000 miles.

1. WARNING: Never remove the pressure relief cap under any conditions while the engine is operating. Failure to follow these instructions could result in damage to the cooling system or engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the cooling system or degas bottle, use extreme care when removing the pressure relief cap from a hot cooling system or degas bottle. Wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly until pressure begins to release. Step back while the pressure is released from the cooling system. When certain all pressure has been released, remove the pressure cap (still with a cloth).
   Drain the engine cooling system so the engine coolant level is below the water thermostat (8575).

1. Remove the hoses from the water inlet connector.
   1. Disconnect the lower radiator hose (8286).
   1. Disconnect the hold-down clamp (12270).

1. Remove the water thermostat.
   1. Remove the bolts.
   1. Remove the water thermostat and O-ring.

1. Inspect the O-ring for damage and replace it if necessary.

Installation

1. Follow the removal procedure in reverse order.

1. Fill the cooling system; refer to Cooling System Draining, Filling and Bleeding in this section.

I would have the cooling fan checked, and have the thermostat changed. An overheated thermostat (overheating caused by something else) will cause problems in the future.