How to Top Off Car Coolant

Coolant, also known as anti-freeze, is vital to your car engine’s health. The cooling system is responsible for transferring the heat created within the engine during combustion to the atmosphere. Coolant mixed with water in typically a 50/50 mix, circulates through the engine, absorbs heat, and flows to the radiator via the water pump and cooling passages to shed the heat. Low coolant levels can lead to the engine running hotter than designed and even an overheat condition which can damage the engine.

Part 1 of 1: Check and top off coolant

Materials Needed

  • Coolant
  • Distilled water
  • Funnel - not required but keeps from spilling coolant
  • Rags

  • Tip: Be certain to use the approved coolant for your vehicle and not the “approved for all vehicle” types. Sometimes the chemical differences between coolants can lead to a “gelling” of the coolant and clogging of smaller coolant passages within the cooling system. Also, buy straight coolant and not the 50/50 “pre-mixed” versions. You will be paying nearly the same price for 50% water!!

Step 1: Check the coolant level. Start with a cool/cold engine. Some vehicles do not have a cap on the radiator. Checking and topping the coolant is done strictly from the coolant reservoir. Others may have both a radiator and coolant reservoir cap. If your vehicle has both, remove them both.

Step 2: Mix coolant and water. Using an empty container, pour a 50/50 mixture of coolant and distilled water into it. Use this mixture to top off the system.

Step 3: Top off the radiator. If your vehicle has a cap on the radiator and no coolant is visible in the radiator, top it off until you see coolant at the bottom of the filler neck. Give it a moment to “burp” as there may be air trapped below. If it “burps” and the level drops a bit, fill it again to the bottom of the neck. If the level remains the same, replace the cap.

Step 4: Top off the coolant reservoir. The reservoir will be marked with MIN and MAX level lines. Fill the reservoir to the MAX line. Do not overfill it. The coolant mixture expands as it heats up and needs room to do so. Replace the cap.

  • Note: Even without a leak in the system, coolant levels can drop over time simply from boiling off. check the coolant level after a day or two or driving to verify the level is still correct.

If your low coolant light comes on or your vehicle is leaking coolant, have a mobile technician from YourMechanic inspect your cooling system at your home or office today.


Next Step

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Recent Cooling System Flush reviews

Excellent Rating

(808)

Rating Summary
753
35
1
5
14
753
35
1
5
14

Lavell

28 years of experience
230 reviews
Lavell
28 years of experience
Chevrolet Sonic L4-1.8L - Cooling System Flush - Vallejo, California
Another great job by Lavell. He was on it. Calls you prior to appointment about questions, thorough in inspection. Prompt and careful during the process. Takes photos and leaves audio notes afterwards. I trust in Lavell to book him again with another appointment. Thanks so much. Glad to find a mechanic to trust and that will come to the house to fix issues.
Infiniti G20 - Cooling System Flush - San Francisco, California
I believe I have described Lavell's qualities where I answered "How would you describe the mechanic?" His knowledge of my G-20 Infiniti and the work that had to be done was excellent!

Angel

5 years of experience
118 reviews
Angel
5 years of experience
Chevrolet Equinox L4-2.4L - Cooling System Flush - Upper Marlboro, Maryland
Angel was very professional. He provided all the services asked for and explained the procedures when I asked him to. He was courteous and friendly.
BMW X5 - Cooling System Flush - Upper Marlboro, Maryland
Arrived early, was very knowledgeable and helpful. Great service all around. Will for sure look to book Angel whenever a service is needed for my cars.

Larry

16 years of experience
114 reviews
Larry
16 years of experience
Dodge Avenger L4-2.4L - Cooling System Flush - Columbus, Ohio
Excellent work showed up came prepared got the job done in a timely manner. Overall excellent experience Thank you
Jeep Liberty - Cooling System Flush - Columbus, Ohio
Thank you for all of ur hard work it’s greatly appreciated! Sooo glad u got me back on the road in no time!!! Greatly appreciated!

Joel

11 years of experience
146 reviews
Joel
11 years of experience
Hyundai Sonata V6-3.3L - Cooling System Flush - Flower Mound, Texas
Joel arrived and we discussed repairs. He informed me the intake gasket had been replaced. THE Timing gasket , did not need replacement, he determined clean cover and tighten bolts to manufactured specs. Went to fluid flushes.

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