Can I mix different brands of coolant/antifreeze?
Coolant reservoir is below minimum and I need to top off. Don't know what brand the previous owner used. Can I just buy any coolant from the auto parts store, or do I need specific type?
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asked 1 Aug 2024, 8:34 am by Kate T.
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DO NOT mix different types. There are several incompatible chemistries (IAT, OAT, HOAT, P-HOAT) and mixing can cause gel formation that clogs your cooling system. Check manual for correct type. If you don't know what's in there, top off with distilled water (small amount won't significantly dilute). Better yet, get a full coolant flush so you know what's in there.
Color is NOT a reliable indicator of coolant type. Green used to be IAT but some manufacturers now use green for OAT. Always go by specification in manual (e.g., 'Toyota Super Long Life Coolant' or 'Honda Type 2'). Matching spec matters more than matching color.