Another leak of some kind on son’s truck

[sailor]

Likely a heater core issue. If his coolant is oily then he needs to drain the coolant system and see what's up, it could be a blown head gasket.

Sent from my SM-A135U1 using Tapatalk

Yup.. Pull the oil dip stick, and check for water in the oil..(head gasket)
But, more than likely, just a bad heater core...

[BTLowry]

Heater core

Figure out the inlet and outlet side. Unhook inlet side and disconnect outlet side where it goes back into system (likely on the block somewhere). Hook hose going to inlet up where outlet went back into block (if it will reach) and loop outlet hose back to inlet side of heater core.
Replace heater core when you have time and hook hoses back where they should go.

Hopefully that made some sense

Or if you are not mechanically inclined, send it to the shop for a heater core.

[Cooter]

Thanks for all the info y’all! Will watch some YouTube when I get home and see if its something I want to tackle

[Quackerbox]

Heater core. Very common on that year model. You can pull the two water hoses going to it and fix later this fall when he needs a heater.

This. Shove some steel fuel line or something similar in the two sections of hose and hose clamp together.

Easy quick fix

Sent from my SM-G970U using Tapatalk

[gatt40]

Heater core

[Jon B]

If it ain't the heater core, check to see if it has an aftermarket oil pressure gauge. Mine sprung a leak in my old Camaro.

[Low Fence]

Heater core. Oily stuff is antifreeze