Antifreeze circulates through the cooling system to prevent the engine from overheating. When the engine overheats, oil consumption can rise. The seals and the piston oil scraper rings cannot tolerate overheating, and in the worst case the cylinder head may deform or pistons and cylinders could suffer scratches. Such damage leads to costly repairs. Coolant naturally evaporates over time. A level that falls below the minimum mark on the expansion tank signals a prompt check. It is crucial to decide what can be added to the cooling system and what should not be mixed with it.
Ideally, the same fluid that was originally filled by the automaker should be used. However, many owners, especially those who buy used cars, are not sure what is currently in the cooling system.
The coolant level is checked by the markings on the expansion tank. A level between the minimum and maximum marks is considered normal.
Just add a little water
If topping up is urgent and the amount needed is small, around 100 to 200 ml, distilled or filtered water is suitable. This is safe because the reduction in antifreeze content in a closed cooling system mainly occurs through water evaporation. The cap on the expansion tank reliefs pressure and releases water vapor when necessary.
Ethylene glycol and additives evaporate more slowly. Adding a small amount of water simply replenishes what has evaporated, restoring the antifreeze’s effective freezing point. It does not raise the freezing point beyond its original specification.
Red, yellow, or vegetable color
There is a common myth that coolant color reflects its chemical formula. In reality the color is just a dye, and it can be any shade with no universal standard.
Manufacturers sometimes use specific colors to guide consumers toward their products. Yet the dye color is not the definitive factor. A vehicle’s manual may indicate a preferred coolant, but color alone does not determine compatibility.
Marketing by large brands means some products are repackaged to align with a brand image. A buyer who relies solely on color risks choosing a coolant that is not suitable for their engine. Mixing different types of coolants is strongly discouraged because the balance of additives drives the anti corrosion performance and can be compromised by mixing, reducing protection.
Ask the manufacturer
The best approach is to contact the vehicle manufacturer for guidance, especially if topping up exceeds about 30 percent of the total coolant volume. In many cases it is preferable to replace the entire antifreeze rather than mix several fluids.
Car manufacturers: how to top up or replace coolant at dealers
VAZ
The owner’s manual lists appropriate liquids for topping up. For Largus, XRAY, and Vesta models with H4M engines, use CoolStream NRC concentrate with dilution or CoolStream NRR ready-to-fill liquid according to the specified standard. These liquids appear yellow-green.
For Niva Travel, Niva Legend, Granta, and Vesta models with VAZ-21129 or VAZ-21179 engines, use Sintec Antifreeze according to the standard and Felixcarbox according to the standard. These liquids are red or pink.
According to the Vehicle Operation Manual, visits to a LADA dealer are recommended for topping up or replacing coolant.
Porsche
Only antifreeze agents approved by Porsche should be used, such as Glisantin G40 or Glisantin G65. These can be mixed together. If ordinary water was added in an emergency, restore the correct water-to-antifreeze ratio afterward.
Renault
Each vehicle has its own maintenance and warranty card. The coolant parameters are listed at the bottom right. Use the recommended type for the model, for example Glaceol RX type D for Renault Arkana.
Nissan
In cold weather only antifreeze should be added. Dilute concentrate with water in a 50 to 50 ratio when topping up.
Volvo
Only the original product purchased from an official dealer is advised. If possible, avoid mixing with other liquids.
Hyundai
Coolant level checks should occur when the engine is about 20°C. Depending on the model and cooling system, as well as the reason for the level drop, the topping procedure varies:
- For systems with a pressure expansion vessel, small leaks may occur; add ready-to-use antifreeze as recommended by the manufacturer.
- For non-pressurized systems, add ready-to-use antifreeze if leaks are present.
- For unpressurized systems with a slight level drop due to evaporation, top up with distilled water.
The manufacturer prohibits mixing antifreeze from different brands and recommends using only the original product listed in the user manual.
Subaru
Only genuine Subaru Super Coolant should be used. It is available at dealers in both finished and concentrated forms.
Mitsubishi
The most sensible option is to take the car to an authorized dealer. In many cases coolant loss is minimal, so the focus is on preventing cooling system failures. If the level is slightly lower than expected, consult a dealer to check freezing temperature and top up with the required fluid, whether coolant or distilled water.
Mitsubishi Motors Genuine Super Long Life Coolant or high performance ethylene glycol based coolant is recommended for filling Mitsubishi vehicles.
Audi
Priority should be given to G12 Evo antifreeze.
Expert CommentaryRoman Timashov, Service Director of AVTODOM Altufievo Be careful. Add coolant only when the engine is cold to avoid burns. In cold seasons, avoid using water to balance coolant. Antifreeze diluted with water evaporates faster, causing more rapid engine wear on long trips in subzero temperatures. Remember: maintaining the correct coolant level and timely replenishment is key to safe vehicle operation. |