On 04 Disco is it best to fill the coolant to a little below the cold line indicated on the expansion tank? Reason I ask is I slightly overfilled it by 3/16 of an inch and that's pretty much what the Disco got rid of via the tube that's near the neck of the expansion tank. I did check for exhaust gases and no exhaust gases where found. 04 Disco has new engine with 600 miles.