I have tried the search and can’t find anything specific to my problem, which is. If I top the coolant up to the max a slight water leak takes place until the level reaches min then it stops. I have been quoted £140 to diagnose plus whatever parts are needed plus whatever it costs to fit them. Anyone got any suggestions? Geoff

Stating the obvious (!) but sounds like the expansion tank itself has a leak??

I agree with JCW

However, can you clarify if it leaks as soon as you fill it, or only when the car is running? How quickly does the level drip… and can you see wet under the car? If so, where abouts? Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

Geoff, just make sure you don’t have a leak on the rear heater matrix feed pipe, it runs down the car drivers side beneath the plastic sill cover under the car and is prone to leaking at the joint just behind the jacking point at the rear. If you look under the car with you head just in front of the rear wheel and look up you can see them. I would also change the expansion tank cap as the first port of call, this is the cheapest place to start, other than that its a look around every where checking for any pink stains.