Any advice would be appreciated.
150,000 miles
Months ago I blew the head gasket. The repair shop (Jag specialists) applied pressure to the coolant system to show my through a spark plug hole coolant coming into the cylinder. After the job (they did both gaskets) was done they showed me the gasket and the and the the evidence of the leak and said pressure from the engine, leaking through the gasket into the coolant system cracked the coolant reservoir. Not sure I fully understood this but I accepted it none the less. So they put in a new (jag part) reservoir (lets call this Res#2). One week later the low coolant warning comes on but coolant is full. Back to the shop - It's a bad sensor. They replace the reservoir with Res#3. One month later, I'm smelling coolant. Res#3 is cracked just like Res#1 was. The shop replaces it with Res #4. 1 week later the Low Coolant warning comes on but the coolant is full.

What the hell?
S.

 

The sensor can be replaced without replacing the entire reservoir. The labor may be the same as the tank probably would be removed to fit the new sensor. It might be done in place but the sensor element is breakable.

You, or your tech, might also check the connector to the sensor. If I remember correctly the sensor micro switch is closed when the tank is full, open when coolant is low . . . . or the connection is open.

At least you are not reporting another tank leak.