I'm sure we have discussed that the C20XE gasket is the same as a C20LET gasket .
The old gasket has gone at the back near the water ways .

I have got another gasket and it's genuine GM , the old gasket was GM too though .

This is just to double check realy .

The coolant bottle has pressure on boost and some water comes past the expansion tank top .
Driven off boost there is no problem .

You can see the problem in the pics .

Head gasket has been on a couple of years and not loads of miles .






This is what it was like after had the car for 10k miles or so and needed new gasket .
Going back a few years , but it's in the same area .

It looks like the gasket is going the same way as this >>>