The head gasket leak on these engines is usually just an external leak, not a mixing of oil and coolant. When it needs to be replaced is really when you cannot tolerate the dripping anymore as long as you keep the oil topped off to its proper level.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record