Appreciate there are threads on the forum covering this, but wanted to post this as a reminder, or a heads up to those not aware of the issue...
Driving back from Kent to Bristol today, on the M25 / M4 junction I noticed what I (Stupidly,in hindsight) thought was a lot of spray coming from the off side front (It was raining...). Anyway,this passed in seconds and I didd'nt give it much more thought and carried on home (100miles) with the temp staying at 90 - no adverse issues to make me think anything is wrong.
Arrive at Bristol, first bit of cornering and my temp gauge shoots up / STOP message on the display... Mmm... Immediately pull over and open the bonnet, 2 + 2 put together, assume coolant leak... It was.
The plastic plug on the top coolant rail had popped its top, spraying coolant everywhere.
Luckily,I think being it fairly cold and water remaining in the block, that no long term damage done. I HOPE. Fingers crossed the head gasket it OK, checked oil and cant see any contamination.
R - Have a plastic stopper / plug in the coolant top rail, replace it now. Not later, like I planned to, do it this weekend!
P.S Happy to take recommendations on what I should check to make sure no issues caused by this, assume despite the gauge remaining on 90 it was a LOT hotter in parts