Hi guys, it all started on a track day, there was steam coming out around the expansion tank. I then topped it up and drove home. A few days of normal driving later, it happened, but no steam or signs of leaks. And a few times more. It has just happened again after not happening for a while, I did push the the car a little more than normal, only 5-10mph faster and a few seconds of full throttle over 30 miles.

The coolant light comes but there's not signs of overheating or stuttering. The oil looks fine and so does the coolant! Any ideas? Could it just be the expansion with a slow leak?

Since your track day have you bled the air out of the system? Also after reading on here caps have been known to fail

Sent from my Galaxy S5

Check the radiator, it's an 11 year old car and unless you've replaced the rad it'll be pretty corroded and now probably split.

Edited 1 October, 201411 yr by sepulchrave

Noooo haven't done that :/ ahhh ok I could give that a go I guess!

Check the radiator, it's an 11 year old car and unless you've replaced the rad it'll be pretty corroded and now probably split.

True yeah I'll have a look at it tomorrow thanks

The coolant light comes but there's not signs of overheating or stuttering. The oil looks fine and so does the coolant! Any ideas? Could it just be the expansion with a slow leak?

When you topped it up, did you use the correct coolant fluid?

When you say the coolant looks fine, do you mean it's pink and cloudy or do you mean it's up to the mark and doesn't visibly look low?

If it doesn't visibly look low then there is a reasonable chance the coolant level sensor has failed. That used to happen quite a lot and it's a relatively cheap and easy fix.

change the bottle and cap 

When you topped it up, did you use the correct coolant fluid?

When you say the coolant looks fine, do you mean it's pink and cloudy or do you mean it's up to the mark and doesn't visibly look low?

If it doesn't visibly look low then there is a reasonable chance the coolant level sensor has failed. That used to happen quite a lot and it's a relatively cheap and easy fix.

i've just been topping it up with a bit of water atm, but yeah it looks pink and cloudy! and definitely looks low in the bottle each time the sensor light comes on

change the bottle and cap 

cheers will do!

Should the cap have some kind of seal in it? as mine doesnt and i can now see watermarks and dampness around the cap and underneath the tank where its dripped down!

The seal is not easily visible since it is on the central core which is pushed into the bottle as you screw it down.

 

That core also acts as the pressure relief valve so you would expect to see signs of coolant if it's been releasing pressure as intended.

 

Your cooling system is clearly pressurising more than it's designed to, this is either because it's overheating or because the HG is leaking, it's not likely to be the cap although it's not completely unheard of.