Try "burping" the cooling system and see. Your guess is as good as anyones here as you've got a pretty good guess as to what the problem could be.

I know my cooling system has seen a small reduction in coolant since I bought 1/30/08. Lately it appears to be more than normal since the temps have dropped significantly and I need to put more in just so it doesn't suck up any air as its already at the low mark. Now that I mention it this is in my garage where I check it in the mroning (temps in the 40-50 range). Ugh

 

ok i will try that

 

my reservoir tank is all over the map, sometimes its full, and sometimes it is just above the low mark. Keep an eye on it, but i think you are probably ok. Check under the other cap if its full your cool

 

You can get the coolant tested and see if it has exhaust gas in it, if it does that points to a head gasket. You could also get a leakdown test done.

 

fluctuation in the res tank is normal, just make sure it's on the full line when the motor is cold, that's why it's there. i'm sure they didn't burp the system well enough either, it would take a bit of time tearing the motor down etc and refilling.

 

ok thanks guys, i will check under the other cap and i will keep an eye on it