Lately after driving the car, when I shut it off I pop the hood to cool off the motor faster (and possibly save my wiring harness some stress), a very loud gurgling sound can be heard near the tank and in the wheel well as the coolant level goes down in the tank. I know the expansion tank is in the passenger side wheel well area and my question is: is this a sign of future trouble in my '94 E320 wagon with 176,400 miles on it? The engine temp has been fine even in 90 + F days and the noise stops about 10 minutes after cooling down.