On our 2010 Bav 38 QL ( the original tank) had a leak in the heat exchanger resulting in fresh water from the tank entering the engine heating pipes and forcing water out of the engine header tank when the fresh water pump was on.
Replaced with a "Quick" brand, but had to install a slightly smaller tank to fit. No worries since. I did find that the Quick tank's insulation was not good so I squirted expanding polyurethane expanding foam around the tank. Seems to keep the tank hotter, longer.
Make sure you don't over tighten the hoses to the tank. When our new tank was installed the Turkish installer broke the weld between the pipe connection and the tank.
Craig
" Shirley Valentine"
Gold Coast
Australia