Draining about 1 liter of oil from the CAC cooler after removal indicates which condition?

• A. Normal
• B. Oil indicates turbocharger defect
• C. Engine failure
• D. Oil leak elsewhere

Answer: (A)

When a turbocharged engine uses oil to lubricate the turbo, some of that oil can end up in the charge air cooler as oil vapor or droplets travel with the crankcase ventilation and then drain into the cooler passages. During service, the cooler may contain residual oil from operation. If you drain the cooler after removing it, gravity will pull out this trapped oil. Draining about a liter is within the range of what can be left in the cooler and is considered normal for many designs. It doesn’t by itself indicate a turbo defect, engine failure, or an oil leak elsewhere. Those conditions would typically present with additional symptoms or signs beyond this drained volume.