Hi all,

Overfilled my coolant ever so slightly to check for leaks. Level has dropped to dead on max line when engine is hot. My query is, if a closed system, can coolant be lost by other means besides leakage? Ie. Is there a release valve in the reservoir or some sort of way for the system to purge excess coolant? 

Thanks

Yes there is.  Just look closely. 

The level might even drop a bit more from MAX.  This is OK and why the markings are MIN & MAX and not FILL TO THIS LINE.

My car 2015 Fabia's coolant has been at the same level just above the min level  even if I top it up to halfway between max min level 

17 hours ago, roottoot said:

Yes there is.  Just look closely. 

The level might even drop a bit more from MAX.  This is OK and why the markings are MIN & MAX and not FILL TO THIS LINE.

 

17 hours ago, JoePeddos said:

My car 2015 Fabia's coolant has been at the same level just above the min level  even if I top it up to halfway between max min level 

Thanks both for the reassurance. Relieved me of my anxiety a tad

Just another comment, tale, I replaced the coolant in my 2011 S4, and the official workshop manual said that on refilling, fill the system up to MAX which on that car's tank, is very high! Now I considered that this might be a proper workshop's way of "filling once" after the system had been opened and that any trapped air would get replaced by some of the excess coolant and so the level would drop back in use.

So, getting a bit concerned that after a long fast run, the level had dropped back down to just above halfway between MIN - MAX so when cold and before the return trip the next day, I refilled back up to MAX, got home and the level had again dropped back a bit - but on close inspection, there was traces of dried out coolant on top of the coolant tank, so what had been happening was that the liquid had expanded and forced some out via the pressure cap, after that no more dropping of fluid level - just like it was prior to me opening up that system.

2 hours ago, rum4mo said:

Just another comment, tale, I replaced the coolant in my 2011 S4, and the official workshop manual said that on refilling, fill the system up to MAX which on that car's tank, is very high! Now I considered that this might be a proper workshop's way of "filling once" after the system had been opened and that any trapped air would get replaced by some of the excess coolant and so the level would drop back in use.

So, getting a bit concerned that after a long fast run, the level had dropped back down to just above halfway between MIN - MAX so when cold and before the return trip the next day, I refilled back up to MAX, got home and the level had again dropped back a bit - but on close inspection, there was traces of dried out coolant on top of the coolant tank, so what had been happening was that the liquid had expanded and forced some out via the pressure cap, after that no more dropping of fluid level - just like it was prior to me opening up that system.

So basically all normal and to be expected, I'm guessing, buddy? So I've nothing to worry about?

@CReese123Can you explain the first post please.

Why were you topping up to check for leaks?

 

Had the coolant dropped and was not staying at the lower level?

 

Did your car get built after the issues with Water pumps and the Recall Action / Service campaign that the thread is about at the top of the section?

3 hours ago, CReese123 said:

So basically all normal and to be expected, I'm guessing, buddy? So I've nothing to worry about?

 

In my case yes, just very bad workshop advice and an extremely "big" volume difference between MIN and MAX. With cars with the usual "ball shaped" header tank the difference in volume is much less and even a much lower percentage of the system capacity, I'd think that VW Group carefully thought out what works for MIN and MAX and I'd never bother overfilling as I'd expect that some would get discharged out via the pressure release valve in the cap.

 

As @roottoot asked, really.