2000 Bonneville Coolant

[pepperdeaf]

I have a 2000 Bonneville with 90K miles. Recently, the car began to whistle when I was not accelerating. It whistled loudly at stop lights, etc., but the whistle disappeared when I depressed the gas. The same occurred in park; whistle when in idle, but when the gas was depressed the whistle ceased.

I took the car in and the mechanic replaced the lower and upper intake gaskets, a coolant elbow and upper intake plenium . . . and changed the oil.
The whistle was gone.

About 3 weeks later, we went on a long distance road trip and 100 miles into the trip, the car began to overheat. I pulled over, popped the hood and all my coolant had blown out somewhere. The tank was empty. We had the car towed to the nearest shop. The random shop said the coolant elbow was not sealed properly and replaced it. Luckily the original mechanic reimbursed me for the 2nd mechanic expense.

Now 3 weeks later. . . I think I am losing coolant again. The tank shows coolant about 1-2 inches below the fill line.

I am a novice. Any ideas? Is the original mechanic's work faulty or might their be something else going on? Any guidance would be greatly appreciated.