Life Expectancy of a duramax??

Mines Over 322,000 miles and going strong.

It really is a gross generalization to say the "engine" last for XXX miles. Head gaskets fail as do water pumps and AC units and front suspensions and transmissions and electrical components and of course the very expensive fuel injectors. A friend with a 2002 Duramax has had to replace the injectors twice in the past 3 years with only 25,000 miles of driving. Considering that an injector repair costs as much as a complete gas engine rebuild, the longer life of a diesel engine needs to be taken with a very large grain of salt.

What is also overlooked is that gas engines with 300,000 miles of use are also common. My brother replaced his Toyota with over 340,000 miles on the odometer because the body had rusted out from the salting of the roads where he lives. The engine and transmission were operating perfectly. When tetraethyl lead was eliminated from gasoline in the mid 1970's, engine life was more than doubled.

Taking lead out of the exhaust stream also reduced brain damage in children living near freeways and inner city traffic and when the became adults the crime rate dropped dramatically. Politicians like to take credit for the drop in crime but it was the result of taking toxic lead out of gasoline and nothing more.

It is also a mistake to talk about Cummins engines as though the same power plants in the light duty pickups are like the engines going into tractor rigs on the highways. One thing that the Cummins pickup truck engines do have is the use of much better CAT fuel filters as an OEM item.

Even with the Duramax the reliability varies by model type and production year prior to 2011 and the same is true for the Ford diesel engines with their less than stellar track record.