Got a phone call from the wife yesterday when she was out in the car.

Car fan running frequently, rising temperature gauge so I'm parked up in supermarket car park.

Got a friend to run me over, discovered small dribble from near side front of engine bay but obscured by undertray, nothing in header tank. Filled up about 3 or 4 litres of water restarted car and drove home 5 miles, no over heating occured, removed undertray couldn't find the leak source and no leak since.

Have driven car 3 times about total of 40 miles, no loss of coolant no further increases in temp.

Its got me totally flummoxed


Have left undertray off so if occuring again I can see what's going on but everything looks perfect.

Anyone had this happen and whats the most likely suspect?

As the water level drops, the coolant gets hotter, this increases the pressure in the system and will reveal leaks that are not leaking at a lower temp and pressure...

Get a pressure test done to reveal the leak, early fatties suffered with the expansion tank, not sure if your model was susceptible...

It could be the coolant pressure cap vented some water as the pressure got beyond it's limit...

You may have a minor leak which has caused the coolant to drop over time, small leaks usually don't show as the water evaporates before it is visible to you...  Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Check the pipes attached to the supercharger water pump I had similar it seemed to leak but only when giving it the
Beans Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF