I have a 98 S70 T5 with 135k on it. After driving the vehicle for a while the low coolant light comes on during acceleration. When I check the coolant level the expansion tank is almost empty. There is also a gurgle noise sometimes and the smell of coolant. All the hoses were replaced @110K along with the expansion tank but the upper hose seems to be swollen. When I slowly release the pressure in the expansion tank all the coolant returns to the expansion tank and the coolant level returns to the max line. The t-stat was replaced at 92k. Is air being introduced into the system? Any advice would be appreciated.

 

Yup, u still got some air in it. Fill it, run it and shut it off. Wait about a 10 mins and check ur level. It should got down. Fill run and repeat till it is stable..

 

If you don't have a green cap on the expansion tank go get one ASAP. Other than that, try not to take the cap off the expansion tank when the car is running or hot.