Car is overheating after changing bent valves

Good morning,

The first thing I would do is to check the compression to be sure there is no internal issue.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

https://www.2carpros.com/articles/how-to-test-engine-compression

Did you change the thermostat with the repair? You may have air in the system as well.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

https://www.2carpros.com/articles/replace-thermostat

Roy

Filling-Bleeding

CAUTION: Engine coolant provides freeze protection, boil protection, cooling efficiency and corrosion protection to the engine and cooling components. In order to obtain these protections, the engine coolant must be maintained at the correct concentration and fluid level in the degas bottle.

When adding engine coolant, use a 50/50 mixture of engine coolant and clean, drinkable water.
To maintain the integrity of the coolant and the cooling system:
Some vehicle cooling systems are filled with Motorcraft Premium Engine Coolant VC-4-A (in Oregon VC-5, in Canada CXC-10) or equivalent meeting Ford specification ESE-M97B44-A (green color). Others are filled with Motorcraft Premium Gold Engine Coolant VC-7-A (in Oregon VC-7-B) or equivalent meeting Ford specification WSS-M97B51-A1 (yellow color). Always fill the cooling system with the same coolant that is present in the system. Do not mix coolant types.
Do not add/mix orange-colored Motorcraft Specialty Orange Engine Coolant VC-2 or equivalent meeting Ford specification WSS-M97B44-D. Mixing coolants can degrade the coolants protection.
Do not add alcohol, methanol, brine or any engine coolants mixed with alcohol or methanol antifreeze. These can cause engine damage from overheating or freezing.
Do not mix with recycled coolant unless it meets the requirements of Ford specifications ESE-M97B44-A or WSS-M97B51-A1. Not all coolant recycling processes meet these Ford specifications. Use of such coolants can harm the engine and cooling system components. Do not mix coolant types.

NOTE: The addition of Motorcraft Cooling System Stop Leak Pellets VC-6 darkens Motorcraft Premium Gold Engine Coolant from yellow to golden tan.

1. Add the correct engine coolant mixture to the degas bottle until the coolant level is between the "COOLANT FILL LEVEL" marks
2. Select the maximum heater temperature and blower motor speed settings Position the control to discharge air at vents in instrument panel.
3. Start the engine and allow to idle. While engine is idling feel for hot air at vents.

4. CAUTION: If air discharge remains cool and engine coolant temperature gauge does not move, engine coolant level is low in engine and must be filled. Stop engine, allow to cool and fill cooling system.

Start engine and allow to idle until normal operating temperature is reached. Hot air should discharge from vents. The engine coolant temperature gauge should maintain a stabilized reading in the middle of the NORMAL range and the upper radiator hose should feel hot to the touch
5. Shut the engine off and allow to cool
6. Check the engine for coolant leaks.
7. Check the engine coolant level in degas bottle and fill as necessary

Thermostat-3.0L (4V)

Removal and Installation
1. Drain the engine cooling system.

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2. NOTE: The appearance cover is shown removed for clarity. Separate the thermostat housing.

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3. Remove the thermostat and the O-ring seal from the thermostat housing.

4. NOTE: Clean and inspect the sealing surfaces.

To install reverse the removal procedure.