xitsmike

1995 90QS - I know there is a particular coolant, g12 i think, for some audis. Is my engine one of those that can't take the universal (green) coolant?

Thanks

Catamount90

Covered in great detail if you do a search, but yeah, no green.

nothing

Just be sure to flush the system well first.

moribundman

Audi seems to have switched from using G11 to G12 by '97.

I switched it over to G12 right after I got the new car. Switching is not advisable if your engine has run for a long time on G11.

G11 (green/blue) is not compatible with G12 (pink).
G12 Plus (purple) is compatible with G12 and G11.

If your engine has been using G12, stick with it or with G12 Plus. If your engine has been using G11, stick with it.

xitsmike

Thing is, I'm not sure what was in it when I bought the car a few years ago. Only did a coolant change recently and it was brown. So..I put the green in it, but I was thinking i would flush it really good and switch over. I don't want things breaking because of a wrong coolant.

moribundman

It sounds like the previous owner mixed different types of coolant,, assuming there wasn't any oil in the coolant. You should probably do a coolant systems flush with something like a Prestone flush kit and flush the system really thoroughly. Whether of not you can clean out all the old deposits, some of which may be from the original coolant, is questionable.

Since G12 Plus is compatible with either G11 or G12, it appears to be the safest choice.

sonnigentag

Pentosin G11, it is blue.

A6Gary

Actually, Audi made the switch to the G12 (red) coolant in mid-'96.

moribundman

:-p

Jretal

FWIW, if you flush the coolant system REALLY well, you can easily swap to Dexacool coolant. That's what I'm running now in my A4. Half the price of the OEM, and works just the same.