What is an effective method to identify a cylinder with an internal coolant leak?

Identifying a cylinder with an internal coolant leak is crucial for diagnosing engine problems. Performing a leakdown test is a highly effective method for this scenario. This test involves pressurizing each cylinder with compressed air and then checking for loss of pressure, which can indicate where the leak might be occurring.

When a cylinder has an internal coolant leak, coolant may enter the combustion chamber, causing noticeable pressure loss during the leakdown test. Observations during this test can reveal whether air is escaping into the cooling system via a breached head gasket, or into adjacent cylinders, or if bubbles form in the coolant, which indicates that there's a direct connection allowing coolant to mix with the combustion gases.

Other methods mentioned can also assist in diagnosing different aspects of coolant leaks, but they may not be as direct or effective as a leakdown test. For instance, while using an exhaust analyzer or drawing vapors from the radiator can provide some information, they are not as definitive in pinpointing leaks that are internal to the cylinders. Therefore, the leakdown test stands out as the method that clearly identifies issues specifically associated with cylinder integrity and internal coolant leaks.