Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Lack of Cooling Efficiency › Reply To: Lack of Cooling Efficiency July 22, 2020 at 10:25 am #961918 Richard KirshyParticipant My thought is a flow issue. What is the condition of the radiator? Is it original? if so it may have a partial blockage. May also be a issue with the water pump. It could be the impeller is slipping at higher rpm reducing the flow.