Do you have any service records to determine if any of the cooling components has be replaced? A thermostat that doesn't open all the way could cause an overheating condition, a water pump with a loose impeller could also cause an overheating condition. A block radiator core could cause an overheating situation. It's a 13 years old car so don't expect it to run like a brand new car.

The sweet coolant smell is it from under the hood or inside the car? If it is from under the hood, could have been that a hose let loose and they just replaced the hose, but didn't bother to clean up the mess.

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2006 Infiniti G35
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Audi 4000CS Quattro Sold
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Plymouth "Cuda" 340 Six pack SOLD