BMW 740i Major Engine Damage After Water Leakage From Charge Pressure Cooler
This BMW 740i initially was taken to BMW for assessment. However, after receiving the quotation the client looked for an alternative and chose to bring the car to GP Motor Works. It had to be towed in to our workshop due to the presence of water in the oil system (visible in the oil cap).
Coolant Pressure Test
In these cases, the first step is always to conduct a pressure test to isolate the coolant leak. Our technician could see the pressure gauge going down which is clear indication the coolant system has a leak. But there was no sign of coolant leaking anywhere. It appeared as though the coolant was disappearing.
But further inspection showed the coolant was going directly into the engine. It was leaking through the charge-air pressure cooler into the cylinders. This resulted in the coolant mixing with the engine oil. This is dangerous as it diminishes the oils ability to lubricate the engine parts and can lead to catastrophic engine failure.
Engine Needed To Be Removed
The 740i engine needed to be removed to get access to the head. The inside of the engine looked like the car had a bad case of diarrhoea. The head was sent to engineering and the charge-air pressure cooler was replaced.
Once the head was received, it was installed with new gaskets, head bolts as well as new stretch bolts. The timing was reset. New oil, filters, coolant and anti-freeze etc were added. The engine was then started and run hot to check for leaks.
