Going from Dexcool to anything else REQUIRES a serious flush. Not just a few minutes. Be careful this time of year. Use a heavy duty cooling system cleaner. Run it for at least a week, then powerflush with an inline flush kit. If you have had any "missing" coolant before, use the K&W sealant for another week. Let dry empty for 24 hours. Drain, DON'T, flush then add the green coolant. Dexcool is another useless solution to a non-existent problem.