Oldsmobile/Buick Repair: 3100 GM V6, head gasket failure, losing coolant

Question
My Lady friend has a 02 Buick with the 3100, 70,000 miles that she bought with 40,000. It has never been overheated since she owned it. It has a small amount of oil in the coolant expansion tank and has been losing coolant at the rate of about a quart per 300 miles. There is no anti-freeze in the oil. In order to get the low coolant lamp off I have to overfill the expansion tank, presumably because the low coolant sensor will not read the oil that is in the top of the tank. Naturally, when I have the time, I plan to flush the system of oil and replace the coolant. I am hoping that the only reason it loses coolant is because of the overfilled condition and will be ok until once again oil seeps into the system. I know these motors are prone to both intake and head gasket failure but it I have never seen it unless the motor had at least 130,000. Does anybody think I have a chance of running this thing for an extended period of time before I do major repairs? Can anyone think of any other reason for the symptoms I describe?

Thanks,
Chip (A FORD guy)
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Answer
Hi Chip
I would HIGHLY suspect the intake gaskets.
I have seen them go with as few as 25,000 miles and every mileage above that.
I would plan on an intake job in future, sooner the better.
You COULD try some coolant tablets that GM sells to slow it down, but it, as you know, will not fix leak.
I hope thie helps
Follow post back, if needed.
Pawl