2001 Acura Integra leaking coolant

Hi japostol78,

Apart from the thermostat housing, you should check the pipe to the water pump and heater hoses.

Remember to check your radiator coolant level regularly.

A good working cooling system does not require regular topping up of coolant. If it does, something is wrong.

If the reserve tank is drying up, there must be a leakage somewhere, unless you are overfiling and excess coolant is being push out of reserve tank giving the wrong impression coolant is depleting.

If the reserve tank is not drying up and instead overflowing and the radiator side is depleting, it could be a bad head gasket or radiator cap.

If the engine had just been newly installed, there could be air trapped in the system and this is causing the reserve tank to dry up.

Minimal air trapped would not caused overheating and it would self bleed and problem would be resolved.

How much coolant do you need to refill each time and how long does it take to incur that amont of losses?

Quite often minimalcoolant leakages at the heater core is not easily noted.
During the pressure test, pressure did not drop?
Is the radiator cap new or from the previous radiator?
Did you check the hose from radiator filler neck to reservre tank for leakages?

Yes, after repairs of cooling system, bleeding has to be done to remove the air in the system.

Glad to know you have solved your problem.

Have a nice day.

Different amount of air in system has different results.

Let us put it into volumes to make it easier to understand.

1 liter or more of air.
Engine would overheat and steam would be pouring into reserve tank. Prolonged use would cause damage to head and gasket.

1/2 to 1 liter of air
Overheating might occur when driving in traffic.
Temperature would go down when moving at moderate speed. High speed driving would cause temperature to go up.

For both above situation, steam would be at top part of radiator and the top tank would fail prematurely as steam is beyond boling point of water/coolant.

Less than 1/2 liters.
Overheating might not be noticeable but temp gauge might fluctuate slightly at times. Self bleeding can occur over a few run and stop situation and air would be bled out resulting in the reserve tank running low.