I started my car today (2001 wrx with vf35, sti injectors etc...) and temp gauge started to go up but heaters didnt get warm, so i checked the coolant. Header tank and overflow were both empty... Last time i drove the car was 2 days ago, car was fine. Filled coolant back up tonight, and car drives fine again. No power loss, no puddles of coolant, oil looks clean, no smoke from exhaust once engine is up to temp. Anybody know what might be going on? Thanks in advance, andy

 

From the knowledge I've just aquired either you have a leak or a head gasket issue.