coolant leak

[Joshcott02]

i seem to be losing coolant out this little black plug circled below does anyone know whats meant to go in it or what its for

 

[Cyman]

It's not a good sign. First off make sure the system is bled well and has no leaks. and the ast cap is working or just replace it. If all of that is OK then it could be a sign that your water seals have gone especially if it chucks lots of water out after you park up and turn off. To check this do a champagne test to see if its gone. Also if it chucks a puff of white smoke out on first start up its a sign of water seals.

Hope that makes sense

 

[Cyman]

BTW nothing goes in the black bit its there as an overflow

 

[Joshcott02]

ah right thank you is that plastic bung causing a leak just a sign if the coolant system over pressurising then?

BTW nothing goes in the black bit its there as an overflow

 

[Cyman]

Yeah. That coolant tank is basically filled up as the pressure builds and coolant pushes out into it then as the engine cools the vacuum pulls the coolant back in. If to much is pushed out it just dumps it out the hole.

This is why you need to rule out cap issue or leaks first and make sure caps are right. Top one is flat astute one has the spring