DIY Heater Matrix Change - some teething problems but sorted in the end

[BillyCool]

Question, my heat *so far* is working but not noticing coolant loss HOWEVER hear gurgling coming from dash on ignition start. Does this mean heater matrix needs replacing

Mine did something similar when the matrix was blocked and it had completed a regen. I think it was boiling the coolant and it was somehow "burping" some air. Not sure if I got the noise on start up but mine was linked to the matrix.