Just got my C4 on Monday morning.  Tuesday no issues.  Wednesday while doing a decent amount of stop and go and keeping the air on and off, I got home and it sounded like gurgling coming from the radiator area.  No smoke or hissing, gauge didnt read abnormally high according to what I read.  Car had no performance issues.  Plenty of coolant, oil looked fantastic.  Could this be something to do with how I was driving that day with the AC?  I cant get it checked till Sat.  Should I be worried driving it if i keep the AC off?

It could be a normal sound of the coolant recovery system. How hot did the gauge say it was when you parked it, or while you were driving?
It may just need a new radiator cap, or it may be a little low on coolant. Either way, if it wasn't actually running hot, it is probably nothing to really worry about. I would check the coolant level, and replace the radiator cap, and see how it works from there. If it is running hot, then you need to find out why that is happening.
And by running hot, I mean over 230f in stop/go with the A/C on, or over 215f or so on the road.

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Joel Adams  
My Link

    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

That gurgling sound, is the coolant boiling.

If you are interested in solving your overheating problem send me an email and  I will give you a detailed explanation on how to control your fans manually as well as having the ECM control them.  You can turn on either or both when you want to (mostly when idling or stuck in traffic) & keep the car cool.  This works on 84 to 93's and all you need is 25 feet of 16 gauge wire & 2 toggle switches.    

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