At morning cold starts this Nissan made the grind cavitation sound. And it leaked a bit. Bubbles visible at reservoir. The vacuum side hose leak can cause the system to such air in and form bubbles that join over night and cause the sound. After shortening the tube to form good seal the problem is fixed. No more leaking or sound.
![](https://s2.save4k.ru/pic/IJ-9f2A6Y14/maxresdefault.jpg)