Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Coolant Reservoir Fills, Doesn’t Empty / VSS Issue › Coolant Reservoir Fills, Doesn’t Empty / VSS Issue December 21, 2019 at 3:54 am #895569 Richard KirshyParticipant Did you install a OEM radiator cap or a aftermarket? That would be the first thing I’d look at. Then might do a combustion gas test. As to your speedometer … Do you have the original factory size tires?