Can I Mix the Formulas Together? Is it Really that Bad? You should not mix (OAT-ORANGE) based. said:
formulas with (IAT-GREEN) formulas. The result is typically turning your coolant into sludge due to a chemical
reaction. Keep in mind, (OAT-ORANGE) based formulas are still a developing technology. There are some
“universal” formulas that claim compatibility with other (IAT-GREEN) and (OAT-ORANGE) formulas, but the
only safe bet is to use the same formula that is already in your vehicle. This may change as the (OATORANGE) based formulas continue to develop; however, always err on the side of caution & use the same
type of formula that the manufacturer recommends.
What Should I Do if I Do Mix Them?
Your best bet is to drain & flush your coolant system as soon as possible. The longer two different formulas are
allowed to circulate through your system, the more particles and sludge that can build up. Again, play it safe
and drain the system, flush it with coolant, drain it again, and repeat if you still see particles coming out. When
you finally have it flushed, replace the coolant with what your manufacturer recommends. At the end of the day,
the system was designed to work with the coolant they put in it.