What model engines are found in daimler-freightliner semis?

Answer 1

For a regular, line haul tractor such as the Coronado, Coronado SD, or Cascadia, you'll have the options of the Detroit Diesel DD13 or DD15, or the Cummins ISX12 or ISX15. For smaller models, such as the FL112, which are typically used for vocational trucks or local P&D trucks, the Detroit Diesel 50 Series or Cummins ISM or ISL9 can be had.
The Mercedes-Benz MBE4000 12.8 liter was an available option for Freightliner, Western Star, and Sterling trucks (all three of which were Daimler A.G. subsidiaries; Sterling trucks went out of production in 2009). This engine replaced the pre-02 emissions Detroit Diesel 12.7 liter 60 Series.

Caterpillar engines were available until Cat left the highway diesel market in 2009, following the disastrous debut of the SDP engines. Their repute was already suffering on account of the ACERT engines, and the SDP was the final nail in that coffin.