Slight coolant loss on 2011 Sprinter

I have a 2011 motorhome on a Sprinter base.  I am experiencing a small loss of coolant, about 1 litre every 250 miles, perhaps double that when using it in very hilly conditions.  There is no sign of leaks that I can see, or signs of oil in coolant or vice-versa.  The cap on the coolant container appears to be OK.  Any suggestions as to what might be the cause, or if it's a known issue, please?

Hi
   I would call 1 litre every 250 miles a lot,I would get the system pressure tested.I would go round all the hoses and see if you can tighten them up a little,that being a no cost option.
    regards
        Alan

Thanks Alan

I had this problem with my 2010 sprinter, tried a new pressure cap and I still lost coolant, garage did a pressure test and found a small leak in header tank, new header tank fitted and
after a couple of runs out no problem.
Pete C

groundhog wrote:I suspect it could be the ' water jacket' whatever that is, we had exactly this problem with ours when it was new and it is a known problem with a certain batch fitted to some Sprinters - yours may be one of them worth checking with your dealer? Ours was fixed under warranty but if it is that then I don't know if they would do it as a recall item?

I certainly hope that's not the fault as the "water jacket" is the engine block !

Other than a hose leak the next obvious place to look is the water pump, if that's leaking there will be coolant leaking from the area close to the crank pulley
Any decent garage would use a coolant pressure tester to pump the pressure up to about 20 psi making it easier to locate a leak, the amount you are losing is more than a small leak

Chris