How do I check my coolant level?
Step-by-Step Check
Make sure the engine is completely cold. Never open the radiator cap or coolant reservoir cap while the engine is hot; pressurized hot coolant can cause severe burns.
Locate the coolant reservoir, usually a translucent plastic tank near the radiator. The level should be between the 'MIN' and 'MAX' or 'COLD' lines.
If the reservoir is low, add a 50/50 mix of coolant and distilled water (or premixed coolant) until it reaches the proper level. Do not use plain tap water except in an emergency.
If the reservoir is empty, you may need to add coolant directly to the radiator. With the engine cold, remove the radiator cap and fill it to the top, then top off the reservoir.
What the Levels Mean
A slightly low level is normal over time due to evaporation, but a consistently low level indicates a leak. Check for puddles under the car, white smoke from the exhaust, or a sweet smell.
If the coolant looks rusty, oily, or has debris, the system may need a flush. Oil in the coolant can indicate a blown head gasket.
Some cars have a 'low coolant' warning light. If it comes on, stop driving and check the level as soon as the engine is cool.
Common mistakes
- Checking the coolant while the engine is hot and opening the cap, which can cause serious burns.
- Using only water instead of a coolant mix, which can lead to freezing, boiling, or corrosion.
- Ignoring a slowly dropping coolant level; it often points to a small leak that can become a major failure.
