The Dodge Neon manual says that the coolant is one fluid the dealer is not responsible for. If the coolant that is already present in the vehicle is green, then any quality green coolant will be sufficient. If the coolant is red extended interval change coolant then a Mopar or a name brand red fluid should be used. The extended drain interval fluid (5 years) can be purchased by the gallon from the dealership, part # 05011764AB.

Chrysler sent out a bulletin warning dealerships not to mix the old and new coolants due to seal life issues. If the two are mixed then the 5 year 100,000 mile coolant change interval will be lost, and a more conventional change interval of 2 years or 30,000 miles should be used. The orange coolant also turns brown if the green coolant is mixed in, or if a UV leak detection dye is added to the coolant. This can make it more difficult to detect high levels of rust in the coolant later on.

It is best to use the Mopar coolant because although the GM/Havoline Dex-Cool orange coolant is very similar, it is not identical. Both the Mopar long-life orange and the Dex-Cool are Ethylene Glycol coolants with an Organic additive package, but the Mopar stuff sneaks in one inorganic aditive as well: silicates. Chrysler engineers consider the Mopar coolant to be better than the Dex-Cool or its equivalents.

When mixing coolant, distilled water should be used to avoid any contaminants. Hard water also contains more salts and increases the rate at which parts of the cooling system corrode.