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

 

[Joshcott02]

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

thank you mate

 

[Joshcott02]

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

just getting round to looking into this now parts have came, im not sure if im being stupid here but could i not be the coolant seals have gone, when i parked the car up coolant was fine or no warning lights for low coolant was on, so this has over pressurised cooling down with the engine off eliminating exhaust gases causing this? maybe wishful thinking

 

[Cyman]

Yeah you dont get low warning light everytime.
It works like this engine gets hot expands pushes coolant into overflow when you turn it off engine gets hotter before it cools. but it doesnt draw it back in as it because its no longer under vacuum with a seal gone. This means the overflow tank starts to fill and eventually chucks it out the hole on the top.

Mixture of over pressuring from heat and/or compression leaking through.

When i had it would push coolant out and give a bit of white smoke on cold startup. I pulled the plugs and turned it over with kitchen roll sheets next to plug holes and got a small amount of water out confirming seal leakage. Mind you this wont always happen

I havent read back but im guessing youve got new caps on with the sprung one on the ast and have done champagne test already??

 

[Joshcott02]

Yeah you dont get low warning light everytime.
It works like this engine gets hot expands pushes coolant into overflow when you turn it off engine gets hotter before it cools. but it doesnt draw it back in as it because its no longer under vacuum with a seal gone. This means the overflow tank starts to fill and eventually chucks it out the hole on the top.

Mixture of over pressuring from heat and/or compression leaking through.

When i had it would push coolant out and give a bit of white smoke on cold startup. I pulled the plugs and turned it over with kitchen roll sheets next to plug holes and got a small amount of water out confirming seal leakage. Mind you this wont always happen

I havent read back but im guessing youve got new caps on with the sprung one on the ast and have done champagne test already??

ah right thank you and no not yet will do tomorrow tho