Hello! I am new to the forum and amazed by this community. I have just replaced the cooler fluid tank (white plastic thing next to the engine). It has 3 rubber hoses. After fastening them tightly anew and doing a test drive, I can notice there is cooler fluid coming out from just near the connection to the tank. The hoses look ok and no fault. Was wondering if someone could help me here.

Is this related to the fact system had to 'clean itself'? I have also tried tightening the holding clamps a bit more. The leak does not happen when I am running a test on a cold engine or after driving. Only while driving.

I have checked the valve in the cap and it seems ok.

 

You're going to have to determine which of the hoses is leaking, and pull it off and re-install it. You may find that it's not quite seated correctly, or even that it's not the right size (I recently dealt with that on my BMW). Or (maybe most likely) you have a cracked tank.

Basically, a good hose and a good tank and a good connection always (!) mean "no leak", so one of those three things isn't "good"...

 

Thanks @habbyguy . I think it was neither the tank or the hoses after all.

1. Read a lot of 'bleeding' a new tank properly, push gas on idle until you can see as little air bubbles forming as possible and let the cap release the extra air (before driving, else the air will push out wherever it sees fit and cap might be not enough to release the extra pressure)
2. refastened the clamps

And it did the trick.