Please be advised, if air condition on then within 15 minutes, the coolant burst out of radiator cap (open position)

FILL THE RADIATOR UNTIL COOLANT LEVEL IN RADIATOR STOP DROPPNG.WAIT 5 MINUTES CHECK COOLANT ADD MORE IF COOLANT LEVEL DROPPED ANY.WHEN COOLANT LEVEL STOP DROPPING.INSTALL THE RADIATOR CAP TO THE PRESSURE RELIEF POSITION BY INSTALLING THE CAP TO THE FULLY INSTALLED POSITION AND THE BACK OFF THE FIRST STOP, THIS WILL ALLOW ANY AIR TO ESCAPE AND WILL MINIMIZE SPILLAGE.SLIDE THE HEATER TEMPERATURE AND MODE SELECTION LEVERS TO THE MAXIMUM HEAT POSITION. START THE ENGINE AND ALLOW TO OPERATE AT FAST IDLE FOR APPROXIMATELY 3 - 4 MINUTES.WITH THE ENGINE SHUT OFF,WRAP THE RADIATOR CAP WITH A THICK CLOTH,CAREFULLY REMOVE THE CAP AND ADD COOLANT TO BRING THE COOLANT LEVEL UP TO THE FILLER NECK SEAT.NOW INSTALL THE CAP TO THE FULLY INSTALLED POSITION, THEN BACK OFF TO THE FIRST STOP AND OPERATE THE ENGINE AT FAST IDLE UNTIL THE THERMOSTAT OPENS AND THE UPPER RADIATOR HOSE IS WARM, TO CHECK THE COOLANT LEVEL SHUT THE ENGINE OFF WRAP THE CAP WITH A THICK CLOTH AND CAUTIOUSLY REMOVE THE CAP,ADD MORE COOLANT IF NECESSARY, INSTALL THE CAP TO THE FULLY INSTALLED POSITION.

Have you checked the coolant level? If it is low, the car will run hot, and coolant won't flow through the heater core, which will result in a no heat situation. If this isn't the problem, let me know, I will try to help further.

When the car is completely cool,check the electric fan(s) for smooth rotation.

Clean/check/change the thermo sensor,contact and wire.

===

Excavate air pocket in coolant system / check for head gasket leak

This test will kill two birds with one stone.

===

MAKE SURE THE COOLANT SYSTEM and ENGINE IS COLD!

RAN THIS TEST IN A WELL VENTILATED AREA ONLY!

You will spill some coolant during this air pocket purge test.......BE KIND TO THE ENVIRONMENT and ANIMAL please clean up after the test!

===

Put the front end on a pair of ramp or park your car on a VERY STEEP HILL (radiator facing top of the hill) .

Top of the coolant reserve tank

Let it ran for 10-15 minutes.

Monitor for air pockets escaping from coolant reserve tank.

Small amount of bubbles is OK at 1-5 minute mark

After the thermostat open up (after 195 F warm up) at
5-12 minute mark or after high idle you should see less bubbles.

If you do not see any in rush of bubbles then your thermostat may be partially stuck or rusted badly inside the thermostat hosing.

Give the thermostat host few gentle taps.

If you see larger bubbles surfacing after 15 minutes then should do a hydrocarbon (HC) dye test to test for potential head gasket leak.

Let engine cold down and top off coolant reserve tank.

Start monitor for coolant lost

===

A coolant flush is require every 2 years or 24,000 miles.

I recommend the thermostat that has a relief pop-let to reduce the change of burst radiator and coolant hoses.

Make sure you get a new thermostat gasket,black RTV and fresh coolant for the job.

===
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When the car is completely cool,check the electric fan(s) for smooth rotation.

Clean/check/change the thermo sensor,contact and wire.

===

Excavate air pocket in coolant system / check for head gasket leak

This test will kill two birds with one stone.

===

MAKE SURE THE COOLANT SYSTEM and ENGINE IS COLD!

RAN THIS TEST IN A WELL VENTILATED AREA ONLY!

You will spill some coolant during this air pocket purge test.......BE KIND TO THE ENVIRONMENT and ANIMAL please clean up after the test!

===

Put the front end on a pair of ramp or park your car on a VERY STEEP HILL (radiator facing top of the hill) .

Top of the coolant reserve tank

Let it ran for 10-15 minutes.

Monitor for air pockets escaping from coolant reserve tank.

Small amount of bubbles is OK at 1-5 minute mark

After the thermostat open up (after 195 F warm up) at
5-12 minute mark or after high idle you should see less bubbles.

If you do not see any in rush of bubbles then your thermostat may be partially stuck or rusted badly inside the thermostat hosing.

Give the thermostat host few gentle taps.

If you see larger bubbles surfacing after 15 minutes then should do a hydrocarbon (HC) dye test to test for potential head gasket leak.

Let engine cold down and top off coolant reserve tank.

Start monitor for coolant lost

===

A coolant flush is require every 2 years or 24,000 miles.

I recommend the thermostat that has a relief pop-let to reduce the change of burst radiator and coolant hoses.

Make sure you get a new thermostat gasket,black RTV and fresh coolant for the job.

===
Please post more information by clicking the comment link on the top right corner.

DON'T FORGET to RATE ME if my tip is helpful to you!

Check the coolant level. If coolant drops frequently check for leaks especially on the hoses, radiator and on the water pump. Check if the fan is working by pulling the plug of the temperature sensor on the lower radiator hose. It should run while it is unplugged. Check as well the radiator cap for corrosion. A bad radiator cap would mean steam would escape the system.

When the car is completely cool,check the electric fan(s) for smooth rotation.

Clean/check/change the thermo sensor,contact and wire.

===

Excavate air pocket in coolant system / check for head gasket leak

This test will kill two birds with one stone.

===

MAKE SURE THE COOLANT SYSTEM and ENGINE IS COLD!

RAN THIS TEST IN A WELL VENTILATED AREA ONLY!

You will spill some coolant during this air pocket purge test.......BEKIND TO THE ENVIRONMENT and ANIMAL please clean up after the test!

===

Put the front end on a pair of ramp or park your car on a VERY STEEP HILL (radiator facing top of the hill) .

Top of the coolant reserve tank

Let it ran for 10-15 minutes.

Monitor for air pockets escaping from coolant reserve tank.

Small amount of bubbles is OK at 1-5 minute mark

After the thermostat open up (after 195 F warm up) at
5-12 minute mark or after high idle you should see less bubbles.

If you do not see any in rush of bubbles then your thermostat may bepartially stuck or rusted badly inside the thermostat hosing.

Give the thermostat host few gentle taps.

If you see larger bubbles surfacing after 15 minutes then should do ahydrocarbon (HC) dye test to test for potential head gasket leak.

Let engine cold down and top off coolant reserve tank.

Start monitor for coolant lost

===

A coolant flush is require every 2 years or 24,000 miles.

I recommend the thermostat that has a relief pop-let to reduce the change of burst radiator and coolant hoses.

Make sure you get a new thermostat gasket,black RTV and fresh coolant for the job.

===
Please post more information by clicking the comment link on the top right corner.

DON'T FORGET to RATE ME if my tip is helpful to you!

take fan belt off so water pump does not turn. take thermostat housing off. make sure water level is close to top of thermostat housing (inside) start it, look for air bubbles... If you get them it is due to leaking headgasket, this will be the cause of your overheating and I suspect it's pushing water out too... Just a guess with the limited details.

You may want to reconsider if the fan is working at it's full potential.It seems when the vehicle is moving the extra air flow compensates for the fan not blowing hard enough.Check for radiator obstructions such as leaves and debris.And check for small leaks.Also there may be an air pocket in the system which can still seem like the system is full.With vehicle cold take off radiator cap and run vehicle.Turn on heat to highest setting (blowing).When vehicle reaches thermostat rated temperature(opened thermostat) you will see coolant go down in radiator.Fill radiator while the engine rpm's are up (have someone hold the throttle to where the rpm's are at about 1800) then put on cap before returning to idle.This should remove the pocket if there is one

Do the air purge test below.

The fins/turbine on water pump can be totally worn out.

====

When the car is completely cool,check the electric fan(s) for smooth rotation.

Clean/check/change the thermo sensor,contact and wire.

===

Excavate air pocket in coolant system / check for head gasket leak

This test will kill two birds with one stone.

===

MAKE SURE THE COOLANT SYSTEM and ENGINE IS COLD!

RAN THIS TEST IN A WELL VENTILATED AREA ONLY!

You will spill some coolant during this air pocket purge test.......BE KIND TO THE ENVIRONMENT and ANIMAL please clean up after the test!

===

Put the front end on a pair of ramp or park your car on a VERY STEEP HILL (radiator facing top of the hill) .

Top of the coolant reserve tank

Let it ran for 10-15 minutes.

Monitor for air pockets escaping from coolant reserve tank.

Small amount of bubbles is OK at 1-5 minute mark

After the thermostat open up (after 195 F warm up) at
5-12 minute mark or after high idle you should see less bubbles.

If you do not see any in rush of bubbles then your thermostat may be partially stuck or rusted badly inside the thermostat hosing.

Give the thermostat host few gentle taps.

If you see larger bubbles surfacing after 15 minutes then should do a hydrocarbon (HC) dye test to test for potential head gasket leak.

Let engine cold down and top off coolant reserve tank.

Start monitor for coolant lost

===

A coolant flush is require every 2 years or 24,000 miles.

I recommend the thermostat that has a relief pop-let to reduce the change of burst radiator and coolant hoses.

Make sure you get a new thermostat gasket,black RTV and fresh coolant for the job.

===
Please post more information by clicking the comment link on the top right corner.

DON'T FORGET to RATE ME if my tip is helpful to you!

Open the radiator cap when the engine is cool and check for any foaming or bubbles when the engine is running. Also check the oil dipstick for a creamy residue which indicates water has mixed with the oil. Either of these point to a blown head gasket which causes overheating even when the cooling system is good.