This Mitsubishi Triton came into the workshop with overheating issues.

We performed a TK test which failed. The head check combustion leak detector is designed to check combustion gases in the cooling system. It works by analysing the air within the 'air cushion' above the radiator coolant level. When CO2gas is detected in petrol engines, the blue fluid will turn yellow, or green in diesel engines.

When an engine overheats, the temperature of the coolant inside the engine increases rapidly, causing it to expand beyond its intended limits.

The excess pressure created from the expansion can result in several problems. Firstly, it can cause the coolant hoses to burst, which can result in coolant leaking out of the engine and onto the ground. This, in turn, causes the engine to run even hotter, creating a vicious cycle that can lead to complete engine failure if left unchecked.

Additionally, overheating can also damage the cylinder head gasket, which is responsible for sealing the combustion chambers from the coolant and oil passages. Once the gasket is damaged, it can allow coolant and oil to mix, which can cause serious engine damage, including cracked cylinder heads and pistons.

Upon further investigation, we removed the EGR pipe to inspect the EGR cooler and found coolant inside the cooler.

When coolant gets into the EGR cooler is the possibility of corrosion and rust forming inside the EGR cooler. The EGR (Exhaust Gas Recirculation) cooler is designed to cool down the hot exhaust gases from the engine before they enter the intake manifold. However, when coolant enters the EGR cooler, it can mix with the exhaust gases, creating a corrosive mixture that can cause severe damage to the cooler and other parts of the engine.

An overheated engine is a severe problem that needs to be addressed immediately. The longer an engine is allowed to run hot, the greater the chance of significant engine damage occurring.

As mechanics, it's our responsibility to educate our customers on the importance of maintaining their cooling systems and being aware of the signs of overheating. With proper care, an engine can run smoothly and efficiently for many years to come.