If a motor vehicle engine consumes an abnormally large amount of cooling water, there is usually a defect. If the cooling water does not visibly flow through a leak in the cooling system, the cause may be a defective cylinder head gasket. In this case, the cooling water enters areas of the engine that are not part of the cooling system and is sometimes vaporized during the combustion process. In this context, experts commonly refer to the engine as “pulling water”.
If the engine draws in water, there may be a defect in the cylinder head gasket. This gasket is fitted between the crankcase and the cylinder head of the combustion engine. Among other things, it seals the engine oil and cooling water channels. As the cylinder head gasket is exposed to constant thermal stress, it will wear over time. This can be seen, for example, by the formation of cracks in the material. If the gasket is defective, engine fluids can mix or penetrate the crankcase. In this case, the cooling water often penetrates into areas outside the cooling circuit, e.g. the oil circuit or combustion chambers. In the latter case, the cooling water evaporates during the combustion process and is expelled with the exhaust gases through the exhaust system. You can sometimes easily recognize it by the white steam escaping from the exhaust.
Even when buying a second-hand car, it is often advisable to pay attention to this during a test drive. If a large amount of steam is emitted, you should turn off the engine for safety reasons and have the car towed to a garage or call a breakdown service. A defective cylinder head gasket can also cause a mixture of cooling water and engine oil. The cooling water often has a brownish discoloration or there are watery components in the engine oil. This is not the only reason why you should check the condition of the cooling water and engine oil yourself from time to time. Signs of a defective cylinder head gasket should never be taken lightly, because the engine can be severely damaged if it continues to run with a defective gasket. You must have a defective cylinder head gasket replaced in a specialist workshop. Repair is not easy and requires expertise and special tools.
An occasional look under the hood of your own car never hurts. This way, defects can often be detected in advance. In addition to checking cables and hoses for visible damage, such as rubbing during operation or marten bites, you should also take a look at the fluid tanks in the engine compartment. Often, the only thing you should look at is the level of the water tank for the wiper water, but you should also pay attention to the engine cooling water tank. The exact position of the coolant tank is usually listed in the vehicle owner’s manual, and it usually also states the range in which the water level should be.
The coolant level is often visible from the outside through the usually clear tank. If the water level is between the minimum and maximum marks, everything is in the green zone. You should also check the color of the cooling water immediately. Cooling water is always colored by the added antifreeze, usually colors such as blue, green, yellow, red or sometimes pink. If, however, brownish or dark bands are visible on the coolant, it is likely that engine oil has penetrated the coolant, indicating an engine defect such as a broken cylinder head gasket. A specialist can reduce the defect.
However, a low coolant level or loss of coolant can also be caused by something other than a defective head gasket. For example, the coolant tank or associated cover may be defective, resulting in leakage or evaporation of water. Sometimes coolant also leaks unnoticed through defective or porous radiator hoses.
This is not always visible at first glance, especially if the defective part of the radiator hose is covered and cannot be seen. In the event of a leak, a puddle does not always form under the car, where the loss of cooling water could easily be detected. Coolant often only leaks when the engine is running and sometimes evaporates unnoticed on hot engine parts. In any case, if coolant consumption is abnormally high, the vehicle should be checked quickly by a specialist at a garage.