You most likely have a blown headgasket.
Remove the radiator cap on a cold engine. Turn the heater to hot. Make sure the radiator is full. Start the engine and watch for air bubbles escaping from the radiator. Add coolant to keep it full. When you see no more air bubbles all air has been removed.
Backpressure in a radiator when cold and the cap is removed can be caused by trapped air bubbles in the cooling system. When the engine is running, the coolant expands and can create pressure in the system, pushing air bubbles to the highest points like the radiator. When the system cools down, the trapped air can create backpressure in the radiator.
If there are no schrader valves to bleed the system, remove the radiator cap, make sure the radiator is full of coolant, turn the heater controls to HOT, start the engine, watch for air bubbles escaping, keep the radiator full, and when you see no more air bubbles escaping, replace the cap. The system is now bled.
Don't! Most cars have a reservoir for radiator coolant ... add liquid to the reservoir. Opening the radiator cap introduces air into the sealed system ... you don't want air bubbles in the cooling system.
Make sure engine is cold then do the following: - Open radiator cap - Start engine - Once the thermostat opens , air bubbles should come out of the radiator neck - Wait until air bubbles stops coming out of the neck - Once the Air bubbles stops from coming out , fill radiator as neccessary - Replace cap and test drive - Repeat as neccessary - Process can take long more than 10 minutes or more depending on how much air is trapped in the system.
Air bubbles in the radiator can be caused by a variety of issues such as a leaking radiator cap, a coolant leak, or a faulty water pump leading to air pockets in the cooling system. It's important to fix these issues promptly to prevent overheating and potential damage to the engine.
Bubbles in the radiator sight glass usually indicate air trapped in the coolant system. When air enters the system, it can prevent proper circulation of coolant, leading to inefficient cooling of the engine. This can result in overheating and potential damage to the engine components. Purging the air from the system and ensuring proper coolant levels can help resolve this issue.
To remove the air bubbles, open the stopcock and the air bubbles will remove
It sounds like your cooling system is pressurised. Check for a blown head gasket by removing the radiator cap while engine is warm and running. Look for air bubbles. If there is air bubbles, overhaul the top end of the engine.
Air bubbles in the radiator with the cap off during a cylinder leakage test indicate a leaking head gasket or cracked cylinder head. This allows combustion gases to escape into the cooling system, creating air bubbles. It is a sign of a serious issue that requires immediate attention to prevent further damage to the engine.
look for bleed plug on thermostat housing or run car with radiator cap off in park with hosepipe in radiator till bubbles are gone.