The 1999 Dodge lineup included several models (Ram pickup trucks, Dakota, Durango), each with different engine options. There wasn't just *one* diesel engine size. To answer your question accurately, I need to know
which Dodge model you're asking about (Ram 1500, Ram 2500, Ram 3500, Dakota, Durango).
The most common diesel engine size in 1999 Dodge trucks was the 5.9L Cummins inline-6. This was primarily found in the Ram 2500 and 3500 heavy-duty trucks. However, smaller models like the Dakota and some 1500s did *not* offer a diesel option.
