Also, check the thermostat housing. If it is a platic unit, you may want to replace it. Yes the plastice unit can be had for as little as $45 if you look around, but you may want to look into getting an all aluminum housing. It's pretty pricey, and can be found on ebay and amazon, but I've had mine for about 3 years and never had an issue. The plastic housing failing was the very first issue I had with the car and it started right after I bought it. I couldn't find the leak, but lost coolant daily, and could always smell it. Finally found the split seam, and replaced it. End of story. No problems since. The original is prone to failure.