If it is running the coolant will be under pressure and above boiling point. Explosive scalding.
Always add coolant to a cold engine. If this is a top up add to the expansion bottle, wait a minute or two for bubbles - repeat until stable.
Screw cap back on, turn over and run for thirty seconds. Off, wait, open cap and top up - if the coolant gets hot during this cycle wait for it all to cool down again.
Coolant should be filled to the radiator to the top when the engine is stone cold. The plastic coolant recovery bottle should be filled 3/4 full when the engine is cold. For the past 50 years cars and trucks have had coolant recovery bottles to PREVENT any air to enter the cooling systems in USA and many foreign cars.
When air is in the cooling system it cannot adsorb heat from the engine or get rid if it in the radiator core.
Turn the engine off. Let it cool down. Add the coolant.
The people who make the stuff know a lot more about it then your mate - so follow the instructions on the bottle!
Put the coolant in first to the required level, then start the engine, and rev it up to bleed any air in the system. You will see air bubbles appear in the expansion Bottle, then the coolant level will drop.
Refill to the correct level again, and still revving the engine, to see if any more air bubbles appear. if no further bubbles show, then switch the engine off. Job Done.
Coolant helps lubricate the water pump, so you'll want to fill it before you start the engine. Add it runs, warms up, and cycles the thermostat it'll push some of the remaining air out of the system, so you'll likely have to add some more after that. And don't forget to turn on the heater so you fill your heater core with coolant, too!
Pull the radiator cap while cool and fill the radiator and reservoir. Leave the radiator cap off and start the motor. Turn the climate control to the hottest setting and direct the air flow to the middle vents. Run the motor around 15 minutes to bring it up to operating temperature and top up the radiator as the air is purged. Watch the temperature gauge and if the motor starts getting too hot turn the motor off and squeeze the upper radiator hose to help move the air trapped in the cylinder heads. start the motor again and keep topping up the antifreeze. Continue until no more air comes out. Check the radiator and reservoir the following morning as many times the system will suck more antifreeze out of the reservoir with the radiator cap back on as the motor cools.
Never add coolant with the engine running. It can blow back and scald you.
Put it into the motor before starting it . Air into a motor could cause problems Ive never heard that before 33 years small engine mech
Trevor has it right. Cold engine add coolent then run motor till thermostat opend and cerculates it. Let cool add more and repeat. That is for a new or drained radiator.
my mate is saying to put coolant in while the engine running to give some air. but the bottle direction says to put the coolant first and after that start the engine.
what is the best way???
.personally I always fill it not running.... then start it up and watch it suck down.... stop it and add more.... repeat.... the beater I drive also has a bleed off on the thermostat housing... you open it a bit till fluid oozes out... I never used it... also remember to fill the overflow take to the cold level.. drive it.. it will level out on its own if your radiator cap is working... then add to the overflow tank... if needed...
...personally I always fill it not running.... then start it up and watch it suck down.... stop it and add more.... repeat.... the beater I drive also has a bleed off on the thermostat housing... you open it a bit till fluid oozes out... I never used it... also remember to fill the overflow take to the cold level.. drive it.. it will level out on its own if your radiator cap is working... then add to the overflow tank... if needed...
always follow instructions on the product they are the experts
