Thanks guys.
What sealant did you use?
The Leon we’ve seen has only done 66k from new.
You’re welcome, sorry don’t remember what he said it was. I just gave him a tenner and he put it in the header tank. It certainly wasn’t one of the well known brands since I didn’t recognise it. Took it back to him after he replaced the thermostat and temperature sensor, it was putting on the low coolant light after a couple of weeks.
I have previously used Bars Leaks with good results and would have happily tried that myself before paying for a pressure test of the coolant system.
66k miles is rather low for a 12 year old car. I know from firsthand experience the VNT turbos like be given decent runs over 30 minutes to get them hot enough to burn the soot off the control vanes. Otherwise you start getting limp mode problems.
Also would be worth checking if the suspension bushes have been replaced yet, since they’ll be due around that age. Mine needed a front end rebuild at 10 years / 70k. Sometimes it can be better buying a car with more average mileage that’s had the common wear/age related work already done.