Audi 5000 - best coolant? G12/G13? Something else?

[Miles07PT]

1979 Audi 5000 (yes, an early one!) with the venerable 2.2 5cyl engine (cast iron block, aluminum head)...

Audi literature says to use "phosphate free" coolant.

Since 1979, a whole lot of VW coolant formulations and specifications have occurred; G11, G12, G12+, G12++, and G13. There's also Zerex G05 and other coolants out there (HOAT)..

What would you recommend and why? Are silicates good or taboo for this cooling system?

And presumably avoid "good old green prestone"-type coolants, etc, yes?

Btw. Car only has 34K original miles, but a lack of coolant changes in the past. (Some sediment). It's getting a flush, and new radiator as part of the refreshment process.

Thanks!

 

[Trav]

Zerex HT12

HT 12

 

[shortyb]

Even though it has aluminum in the system, and some silicate (stabilized, SI-OAT, HOATs) is desirable for MODERN engines, it should be low/no silicate if at all possible. Old Pentosin G11 blue is still available, and I would recommend using that to keep it compatible. It's no nitrate, phos or amine and was original coolant for that vehicle. Some have used Zerex G48, which is very close, but I would avoid G05 though.

Edit: FCP has Fuchs too.
https://www.fcpeuro.com/products/fuchs-coolant-antifreeze-fuchs-maintain-fricofin-v-800359803

 

[SatinSilver]

Would like to see some pictures of the car if you have any.

 

[FowVay]

I'd keep it real and use G11/BMW blue/Zerex G48.