Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 5.7 vortec engine › 5.7 vortec engine November 5, 2019 at 3:57 pm #895220 Richard KirshyParticipant The sending unit is new New does not always mean properly functioning. Which is why I suggest you confirm the coolant temp. could it also be a leak somewhere? Are you seeing a loss of coolant???