Hey, 
I have been trying to find a solution to fix that problem and I can't. Maybe you know. 
function checkStreamIn() 
        local x, y, z = getElementPosition(  getLocalPlayer() ) 
        local playerdimension = getElementDimension (  getLocalPlayer() ) 
         
        streamdistance = 5   
     
        for key, this in pairs( getElementsByType( "vehicle" ) ) do 
            local vx, vy, vz = getElementPosition( this ) 
             
            setElementStreamable ( this, true ) 
             
            if getDistanceBetweenPoints3D( vx, vy, vz, x, y, z ) < streamdistance then 
                setElementStreamable ( this, true ) 
            else 
                success = setElementStreamable ( this, false ) 
            end 
        end 
  
end 
setTimer(checkStreamIn, 1000, 0) 
 
success return always TRUE and elements are still visible.