Since beginning of April, I have gotten the "low coolant" warning 3 times (and I have topped off 3 times). Is this normal? As far as I can tell the engine is not leaking coolant and it is not really low (even though the warning comes on). Further, today it happen when I was stuck in slow moving traffic for half an hour, but then I speed up and the warning went away. Is this is another weird "British" thing? XJ8 Vanden Plas 2003

 

No it is not normal. For low coolant light to come on three times after topping it off in two months, means you're losing coolant somewhere. Small leaks are difficult to detect and a careful examination is needed. The water distribution pipe, thermostat housing, resevoir tank, etc all all plastic items and may develop small hairline cracks that leak coolant slowly under pressure.

When you were sitting in traffic the coolant "settled down" for the sensor to go off and when you sped away the coolant sloshed around enough to make the sensor go off.