The first signs of cooling system failure include the engine running too hot (overheating) or coolant leaks. Although overheating can be a major issue, coolant leaks can also cause the engine to run cold (which is associated with higher fuel consumption and higher carbon buildup throughout the engine). If your new vehicle has a faulty cooling system, whether it is due to a leak or overheating, you may find yourself in and out of the repair shop but unable to find a solution.