Leaky EGR radiators – loss of coolant

Since the introduction of the Euro 4 exhaust gas standard, EGR systems with EGR radiators are increasingly being used. These radiators are not typically wearing parts. However, during the period of their operation, damage may occur.

Damage to the EGR radiators

Coolant is used in EGR radiators to cool the engine. Radiators are made of stainless steel or aluminum. Under unfavorable or unforeseen operating conditions (for example, when the engine is running on fuel with a high sulfur content or on environmentally friendly fuel), aggressive products of the combustion process can be formed. In the long run, this can cause an internal leak with hidden coolant loss. When looking for water losses, cylinder head gaskets or wet cylinder liner gaskets are often replaced unnecessarily and inefficiently.

The most common cause of failure is a leak from the exhaust side. A less common cause is pitting on the coolant side. Improper coolants can lead to corrosion or cavitation. Since the back pressure of the exhaust gases during engine operation is higher than the pressure in the cooling system, the loss of coolant is not always immediately visible. When the engine is turned off, coolant enters the exhaust or intake duct of the engine.

If the EGR radiator is located higher than the inlet and outlet valves, this can cause coolant to accumulate in the combustion chamber of one or more cylinders. When starting the engine, “water hammer” occurs as a result of any serious damage to the piston, cylinder or connecting rod.

To avoid expensive and complicated engine repairs due to the search for the cause of coolant loss, before opening the engine, you should carefully check for a leak in the EGR radiator.