You need to regularly check whether the expansion tank is filled correctly and top it up as necessary. Insufficient amount of the fluid risks its boiling and engine overheating.
Tighten the cylinder head bolts from time to time, about every 4,000–5,000 kilometres. Also be sure to replace the cylinder head gasket at the first symptoms of damage or after every repair that involved removing the cylinder head. Otherwise, due to improper sealing of the joint between the engine block and cylinder head, gases can get into the cooling system, where they can destruct its elements and impair the properties of the service fluid.
The working lifespan of antifreeze is determined by the vehicle manufacturer and stated in its technical specification. For many modern models it is prescribed to replace the coolant every 5 years or 250,000 kilometres.
Never mix fluids of different colours. They have different contents and may contain incompatible components, which leads to change of operating properties of the product and destruction of seals.
When replacing the fluid, it is advisable to flush the cooling system, otherwise, the settled dirt will remain inside.
