Hello folks, just wanted to clarify the cooling system design on 2023+ Powerstrokes.

Is it essentially the same design for all the years 2011 - 2025 (w/ exception of EGR)? This meaning...2 radiators, 2 reservoirs, 2 water pumps, and 4 thermostats. The secondary radiator is internally split into two compartments.
The owner's manual states "Primary cooling system with auxiliary radiator." Not sure what they mean by auxiliary radiator.

To drain and refill, is there a radiator cap and drain valve on both radiators?

Looks like for 2023+, Motorcraft yellow VC-13DL-G coolant is recommended. How many gallons will it take to just drain both radiators?

 

The AUX radiator is the slim one in front of the primary radiator. It is filled through the reservoir similar to the primary. The AUX Rad rather than end caps has end tubes

 

Direct from the Ford 23 Diesel table top book

"The 6.7L Power Stroke® Turbo Diesel engine has two separate cooling systems:
• The engine cooling system, called the primary or high temperature cooling system.
• The powertrain secondary cooling system, a low temperature system that cools the Charge Air Cooler (CAC), fuel
cooler, Diesel Exhaust Fluid (DEF) injector, and on the High Output engine, the turbocharger compressor housing.
Each cooling system uses an independent radiator, belt-driven coolant pump, thermostats, and degas bottle. The EGR
cooler uses the primary cooling system to reduce exhaust gas temperatures. The fl uid coolers located at the front of the
grille opening include:
• Primary radiator
• Secondary radiator
• Air Conditioning (A/C) condenser
• Power steering cooler (separate from the primary or secondary cooling systems)
The secondary radiator is located in front of the primary radiator to allow the powertrain secondary cooling system to
operate at a lower temperature than the primary cooling system. On models designed to carry heavy loads such as dual
rear wheel vehicles and ambulances an auxiliary radiator is mounted under the other radiators and is part of the primary
cooling system. This radiator is connected to the upper and lower radiator hoses using T connections.
The ECT2 sensor has been relocated but is still near the charge air cooler."

 

So it sounds like the Aux Radiator is for DRW and F450+, am I right? F350 SRW doesn't have it?

 

I'm wondering if an Airvac would have any benefit if just doing a simple radiator drain and refill since it's not draining the entire system.