12.7 freightliner columbia part help

Looks like the oil supply line. Just take it off and to the dealership or wherever you’re getting hoses made. Match both ends up to new one. I’d call Dealer first. Lot of parts are still on backorder.

 

Looks like a 1/4” air line covered with wire loom.
Maybe @Big Road Skateboard is familiar with it.

 

My mistake. That’s the airline to the governor. Oil supply line is similar size, maybe a bit larger. Located lower down. The big one (pictured) is air intake, runs from intake manifold. The SS (pictured) is air output, runs to air dryer. ( usually to a non SS hose first, then to dryer) . Other 3/4 “ (pictured) is coolant, runs to block. Other coolant hose (not pictured) is probably a short one on the other side, running to the block. So you have a total of 3 air line’s including the small one to the governor . Total of 2 coolant lines. Total of 1 oil supply line. Oil returns to block through the compressor body.

 

‘ac’ compressor, or ‘air’ compressor? Looks like air compressor to me.

 

I think you and @Rideandrepair got it covered