Coolant evaporating or leaking ?

[elias]

Hi to all ,
I noticed after around 150hours on the D2 55 that coolant level was on low line limit . It regularly goes high and low, high when engine is running or hot . But I think it had lost some . It has been serviced recently , new flanges /gaskets and everything . I checked the cap of the expansion tank and had some white residue and also the hose on the cap on the heat exchanger I can see some moisture . Is it normal that every 200 hours  to need around 100ml refill?

[Jake]

Check for evidence of any leakage around the hose connections and the filler neck on the heat exchanger.  Coolant that evaporates will often leave residue.  My filler neck slowly leaks a bit of coolant when the engine is hot.  I'm going to attend to it very shortly.

Jake
Bav 44 2004

[elias]

I saw some residue on the expansion tank cap and the hose , I ll keep a closer watch . Thanks

[Jess21]

When recently filled with new cooling liquid, some air bubbles might be enclosed in the boiler and motor. When the motor is in use for a couple of hours you probably need to add some cooling fluid (1/2 .. 1 liter is possible).
So: first wait and see...