I had a small leak in the reservoir tank that I fixed on my '07 XJ8. Now the cooling fan runs almost all of the time. Could it be that I now have the wrong mixture of coolant to water since I have topped off the reservoir tank with water on a few occasions or maybe a bad thermostat? Any suggestions would be greatly appreciated.

 

Are you sure it is full? How many miles has it been driven since the tank was replaced? It is possible that if it overheated there may be damage to the t-stat. An air pocket could cause this problem, coolant mixture could not.