Skip the auto shop - Our mechanics make house calls

How to Top Off Car Coolant

coolant being topped off

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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...


Related questions

Q: While driving, I heard loud squeaking noise. I pulled over and saw white smoke and pink coolant all over the ground. what is this?

Some of the coolant has come out of the engine, of course, because there is a leak. Your mention of a loud squeaking noise makes me think water pump, as in seized water pump, however there are other possibilities so...

Q: Would a water saturated air filter result in an immediate engine seizure 2016 VW Touareg

Hi there - the answer to your questions is "maybe". Since water does not compress at all, it takes very little water in a cylinder to cause "hydro-locking" which will cause serious damage to your engine. Perhaps a bigger question...

Q: Hi, I have a 2003 pontiac sunfire that is getting water in my engine. It looks like water is leaking from somewhere between my eng

Engine coolant can leak externally through a hose, radiator, water pump, etc. or internally due to a leaking head gasket and sometimes a leaking intake manifold gasket depending on the engine design. External leaks are typically found by simple pressure...