I have a 2000 Range Rover which overheats or the temp gauge increases in traffic. I've put coolant but it still comes on. Any suggestions? Also what would you recommend for tune ups because it feels like it's lagging really bad. Thanks all for the help.

 

Yikes. How fast is it drinking coolant? Also check your oil dipstick and fill cap. If you see any gray/milky coloring..contact your accountant.

MOST IMPORTANTLY: STOP DRIVING THE ROVER.

With lagging/power loss, and overheating + coolant loss....my non-professional opinion is head gaskets.