Thermostat failure

[Johanj]

Hi Guys, sorry to dig up a thread again but I have a issue that is bothering me:
My X5 3.0D runs good no issues but after some "spirited driving" or when towing, the temp will climb to just above the half way mark and when driving normal or slowing down the temp will drop back to just below the halfway mark. Is this normal behaviour or should the temp be more constant? can the Thermostat fail in a halfway open position causing it not to circulate fast enough when the engine needs the extra cooling? I have checked in the expansion tank and the water from the inlet in the cap has a steady stream and spurts through when revving it a bit, telling me the water pump is giving good circulation. It does leak a little bit of water, haven't found the exact spot yet but somewhere under the expansion tank, could that be that second thermostat?

 

[Solo Man]

Those cars normally have two thermostats. The normal one and then one for the egr (a plastic pipe with in-built thermostat) running I think just below the stainless steel square thingy that you can see above the clutch fan. I found that on one of my previous 3l diesels, it was the egr thermostat that was not working. Go to Realoem and check it out there or go to the agents with your vin number. I doubt if you will get that part from any one else.