Hi there, 

 

1st time posting and looking for some advice. 

 

I've got a 2015 Skoda Octavia 2.0 Diesel, the vehicle is intermittently losing coolant, It appears to be losing it from around the expansion tank, It's been pressure tested twice and is fine, what could be causing the coolant to boil and throw is out of the tank, we've tried a new coolant cap but that hasn't helped, we were going to change the thermostat but garage said it's a very timely job inlet manifold off to change it which seems a bit excessive to me. 

 

Any ideas where to look at all please? 

 

Thanks, 

Has the garage any experience with VAG engines?

It could be one og many things and ideally need to see if the coolant is fully circulating around the engine.

Have you had the coolant pump changed at all?

They are just a general garage I'm afraid, they changed the water pump and timing belt about 15k miles ago for us, could it possibly be the water pump? Thanks 

Not sure if this could relate to a silica bag in the expansion tank, but you might well have this, as your engine is similar to mine.