Has Ford decided there was a problem with the G05 coolant? Or are their new coolants a catch all replacement?

 

I don't know, I wonder too.

 

The maze of coolants, especially if you have multiple vehicles, is wildly confusing.
My wife takes her Nissan to dealer so scratch one except experience shows they don't properly air tires or install cabin air filter correctly.
My 01 F-150, I'm sure Dad paid not attention to what was in it new and the old green since. I'm tired of the short maintenance and time for something else.
My 10 Lincoln MKS had the yellow from new. That does not agree with owner's manual but some Ford charts and it will stay the same.

Part of the confusion is Ford does not know its own color system. My manual for 2001 f-150 shows as an alternate possibility yellow coolant. If you check the part number it translates to Ford Gold, not yellow. Then if you get a Ford chart showing coolant use where they at least distinguish the Gold as yellow and the newer yellow as DY, dark yellow, that chart disagrees with both vehicles I own. Example, it claims yellow, Ford Gold, was not used until in the calendar year of 2002, part way in the build of model 2002. Totally disagrees with my owner's manual.

 

To make matters worse, there is H-OAT and OAT. Supposedly you can't mix them.

 

Per Ford:

Backward Compatibility/Use of Motorcraft® Yellow Antifreeze/Coolant with/in place of Motorcraft® Orange Antifreeze/Coolant and Motorcraft® Specialty Green Engine Coolant with Bittering Agent Ford Engineering has approved the use of yellow-colored Motorcraft® Yellow Antifreeze/Coolant (Ford specifications WSS-M97B57-A1 and WSS-M97B57-A2) to service all Ford, Lincoln, and Mercury vehicles factory-filled with the following antifreeze/coolants: • Orange-colored Motorcraft® Orange Antifreeze/Coolant (Ford specifications WSSM97B44-D and WSS-M97B44-D2) • Dark green-colored Motorcraft® Specialty Green Engine Coolant with Bittering Agent (Ford specification WSS-M97B55-A) Important: Do not use Motorcraft® Yellow Antifreeze/Coolant to service Ford, Lincoln, and Mercury vehicles factory-filled with any other Motorcraft® antifreeze/coolant. In the case of these vehicles, Motorcraft® Yellow Antifreeze/Coolant is not compatible and therefore is not approved for use. Continue to service these vehicles using only the correct recommended antifreeze/coolant. Service Information for using Motorcraft® Yellow Antifreeze/Coolant with/in place of Motorcraft® Orange Antifreeze/Coolant and Motorcraft® Specialty Green Engine Coolant with Bittering Agent Topping off, Draining and Refilling: • Motorcraft® Yellow Antifreeze/Coolant can be used to top-off or entirely replace (drain and refill) antifreeze/coolant in vehicles factory-filled with Motorcraft® Orange Antifreeze/Coolant and Motorcraft® Specialty Green Engine Coolant. Flushing: • Flushing the cooling system is not required prior to entirely replacing (draining and refilling) Motorcraft® Orange Antifreeze/Coolant or Motorcraft® Specialty Green Engine Coolant with Bittering Agent with Motorcraft® Yellow Antifreeze/Coolant if the cooling system is not contaminated. Normal Scheduled Maintenance: • Follow the factory-fill antifreeze/coolant change-out intervals in the Scheduled Maintenance section of the vehicle’s Owner’s Manual. o Example: A 2019 Ford Escape factory-filled with Motorcraft® Orange Antifreeze/Coolant that is topped-off/replaced with Motorcraft® Yellow Antifreeze/Coolant must adhere to the antifreeze/coolant change-out intervals in the 2019 Ford Escape Owner’s Manual’s Scheduled Maintenance section - “initial replacement at six years or 100,000 mi (160,000 km), then every three years or 50,000 mi(80,000 km)”.

https://www.motorcraft.com/content/dam/ford-motorcraft/en_us/motorcraft_global/products/lubricants/quick_reference_charts/antifreeze_coolants_english.pdf