Antifreeze PEAK or VALVOLINE

I personally use Peak brand coolant, and I've never had an issue for 100K+ miles.

Even though most will say to stick with G12/G13, I think that is where that "sand" comes from. I decided last year to completely drain the system - including engine block - and converted to Peak antifreeze. I have not had any problems since.

I run it in my 2010 Tundra. after much research and not wanting to spend the $$ on overpriced toyota branded coolant I swapped out the system when I hit 100k (Valvoline asian). That was maybe two years ago. 30k miles later no issues.

There's Zerex (Valvoline) Asian car coolant (prediluted) that's made in 2 colors, blue and red, and it's supposed to be compatible

Call Valvoline (Zerex), which makes both green and Asian coolants. Most likely the green you bought is not like the green sold 20 years ago.

From the manual: "The manufacturer recommends using MOPAR Antifreeze/Coolant 5 Year/100,000 Mile Formula HOAT (Hybrid Organic Additive Technology) or equivalent." Remember that the Routans are really Chryslers in disguise, so no need to go exotic brands on fluids. So you can try this: Valvoline Zerex ZXGO51 G-05 Antifreeze.