Yeah, the fans should only turn on if the temp gets too high, or the AC is switched on under a certain speed.

Well, if your fans aren't coming on it may be a bad sensor. I believe the one that the computer reads is mounted in the water pump housing. It should be the exact same sensor that is used in the head (you might want to double check), I would first try replacing that sensor and then try the idle test again and see if the fans turn on.

Yes, the radiator cap can leak quite a bit of coolant, so you might want to spend a few bucks on a new one if yours is old.

Um, generally when I have air in the system, it will cause my temp gauge to jump around.

Good luck, and let us know what you find out.

 

After a couple of days of driving, my Z doesn't seem to be losing any coolant. The reservoir and the radiator are both full. I have not experienced any overheating since the initial incident on the highway.

if an air pocket was caught in one of my heads, could that cause the temp guage to indicate overheating?

I guess I should be happy that the symptom has gone away.

Thanks again for your help