MARCH374 -

Zerex G05 by Valvoline is another suitable substitute. However, if your Bimmer currently has BMW coolant and all you wish to do is top it, go to an independent mechanic to get it done. If you want to use something other than BMW coolant, then you should do a complete drain and replace and avoid mixing.

A gallon of BMW coolant (undiluted) is $18.95 at bavauto.com. A gallon of Zerex G05 (undiluted) is $11.00 at Kragens.

Regards, Mike