Engine coolant is the lifeblood of your car’s cooling system. It helps in boosting the engine’s health and performance. If you’ve driven your car for several years, you know that adding coolant is a step you can’t skip.
And like other vehicle fluids, you should observe some precautions before and after adding engine coolant. Most drivers wonder how long they should run the engine after adding coolant. The truth is you should not run the engine immediately after adding coolant. Doing so can drastically reduce the coolant’s efficiency.
So, how long should you wait?
Keep reading and learn how long to run engine after adding coolant. You’ll also learn tips for adding coolant to your car.
Question: How Long to Run the Engine After Adding Coolant
Once you’ve added coolant to your car, wait for a few minutes – at least 15 minutes – to prevent it from receding. You can do this if your engine is cold.
The coolant has air that’s not needed in the cooling system. If you run the engine immediately after adding the coolant, the air will reduce its efficiency.
The air in the coolant mixture can lead to the formation of air pockets in the cooling system. These air pockets reduce or block the flow of coolant. As a result, the engine overheats, and the coolant boils in the reservoir.
When this happens, excessive heat causes premature wear and damage to engine components. The engine can also lose power and eventually stall. Additionally, the radiator or hoses can burst and leak coolant.
Waiting for at least 15 minutes prevents such instances from occurring. The goal is to allow the coolant and air to separate. Once this time is over, run the engine to circulate the coolant. You can inspect coolant circulation by observing it through the radiator filler neck or hoses.
If air pockets form in the cooling system after adding coolant, you’ll need to bleed it out. You can consult the car owner’s manual to learn how to bleed air from the system.
Answer: How to Add Coolant in an Overheated Engine
Unlike a cold engine, you should not add coolant if you have an overheated engine. The cooling systems get pressurized when the engine overheats. If you remove the cap to add coolant, the pressurized hot coolant can cause severe burns.
The filler cap can also be extremely hot and unsafe to touch. Moreover, adding coolant to a hot car can cause severe damage to the engine. The coolant causes sudden temperature changes, resulting in cracks and corrosion in the engine.
So, if you have an overheated engine, allow it to cool down for up to 30 minutes. This time can vary depending on how overheated your engine is.
Before adding the coolant, park your car on an even surface and turn the engine off. Allow the engine temperatures to drop to safe levels. Once the engine is cool, you can open the cap and add coolant without worrying about burns or damaging the engine.
Question: What To Do After Adding Coolant
You now know how long to run engine after adding coolant. But after adding the coolant, you’ll want to ensure it works efficiently. Below are some of the things you should do after topping up the coolant level:
Close the Filler Cap
The radiator or reservoir has a filler cap that ensures the coolant remains within the system without getting spilled. After filling the liquid to its maximum level, screw shut the cap as tightly as possible.
Inspect for Coolant Leak
Run the engine to allow coolant to circulate the engine. Then stop the car and check for coolant leaks. Look for a light-colored liquid around the cap, hoses, or engine compartment. You can also check if there’s colored fluid dripping to the ground from the cooling system.
If your coolant level goes down faster than expected, you might also have a coolant leak. So, inspect the cooling system and fix the leaking parts.
Ensure the engine cools down before checking the coolant level in the radiator. Alternatively, allow a mechanic to check the system and fix any leaking or defective parts.
Observe the Engine Temperature
Whether you have an old or overheated engine, you should observe its temperature after adding the coolant.
Typically, you’ll add coolant if the level is too low. After adding coolant, give it about 15 minutes before starting the engine. Then, turn on the ignition to check the engine temperature indicator. You can drive the car if the temperature is within the prescribed range.
You’ll want to drive for 2-3 miles to observe the temperature. Check the engine temperature indicator to know if the coolant is working well. Ensure the engine’s temperature stays at the normal range.
If the engine doesn’t overheat, you can continue driving. However, if it overheats, the cooling system might have issues that need addressing. Park the car and inspect the system.
Question: How Often Do I Need To Add Coolant?
Checking and maintaining coolant levels is critical to your vehicle’s maintenance. So, always check the coolant level at least once a month. You can check more often if the engine’s temperature is too high. Top up the coolant if the level goes below the minimum point.
Maintaining coolant levels and its condition ensures it remains effective for a long time. Generally, the coolant should last 2-5 years (24,000 to 31,000 miles) before becoming ineffective. The time for changing the coolant in your car can vary depending on the car and coolant type.
Whether pre-mixed or pure coolant, you’ll need to determine its lifespan once added to the car. Depending on the driving conditions, most premixed coolants will remain effective for 3-5 years.
If you use pure coolant, mix it with distilled or deionized water to ensure it lasts up to 5 years. Mixing this coolant with tap water reduces its lifespan to 2-3 years.
Check the manual to know when to change the coolant in your vehicle. A licensed mechanic should also help you understand when to add or change coolant.
Question: Should I Add Coolant in the Reservoir or Radiator?
Learning how long to run engine after adding coolant is not enough without knowing where this liquid goes. Cars have a radiator or reservoir where the coolant goes. So, before adding the coolant, determine if your vehicle has a radiator or reservoir.
Most modern cars made after 2005 feature a reservoir – a translucent plastic tank – for storing coolant. Manufacturers mount this tank on the engine bay. You can easily see this plastic tank thanks to the coolant’s color.
The reservoir has a minimum and a maximum level. When adding coolant, ensure it reaches near the maximum level. Adding coolant above the maximum level leads to wastage.
If your car doesn’t have a reservoir, you’ll need to add the coolant to the radiator. Locate the radiator cap and remove it. Then add your coolant as guided in the owner’s manual.
Answer: Additional Tips for Adding Coolant
Use the recommended coolant for your car: Consult a professional to know which coolant variant suits your vehicle. You can also look for the coolant’s contents to know if it’s compatible with your vehicle.
Know the coolant’s composition: The coolant can be pre-mixed or pure. If you buy pre-mixed coolant, add it directly to your car. This coolant is convenient as you don’t need to mix it with water. If you purchase pure coolant, dilute it with deionized water before adding it to the car.
Check the level and condition of the coolant: You will only add coolant if the level is low – below the maximum point. You can also add if the radiator or reservoir is empty.
Before adding the coolant, check the condition of the current coolant. If the coolant has lost its original color and appears dirty, remove it and add a new coolant. Remember to clean the reservoir or radiator to remove the sludge.
Don’t mix coolant brands: Coolants from different brands can have varying ingredients. When mixed, these ingredients can react and cause the coolant to coagulate. If you have a different coolant brand, remove the current coolant from the car and add the new brand.
Use water in absolute emergencies: You can add water to the cooling system, but do so in emergencies. For example, you can add water if the engine overheats and you can’t access the coolant.
Final Thoughts
Hopefully, this article helps you know how long to run engine after adding coolant. If you’ve added coolant to your vehicle, wait at least 15 minutes before running the engine. Doing so allows the coolant and air to separate. Lastly, check and maintain the coolant level to increase the engine’s performance and lifespan.