Nanainmk

I have got the use of a vacuum bleeder if required, was just going to drop everything from bottom hose and refill with g12+ with vacuum bleed knowing there will be some original coolant in the system

I have just swopped the expansion tank with the silicon bag in it for a new design one. The radiator doesn't have a drain plug in it so if I pulled the bottom rad hose off there would still be coolant in it. Would it be OK mixing the original coolant with some g12+ or should I flush as much out as possible with water from a hosepipe. The bag had not split thank goodness.

My Octavia Vrs facelift 2018 has had problems starting a few times. Everything it is after a rainy day so guess water is getting into somewhere it shouldn't.The battery voltage with the engine running is sometimes only 12.9v and sometimes 14.5v as normal. I think one of the relays is failing. Here is the obdeleven error codes. Can anyone help me? Trouble codes: P065800 - Actuator Supply Voltage "A" Circuit Low Intermittent P068A00 - ECM/PCM Power Relay De-Energized Performance - Too Early Intermittent P056200 - System Voltage Low Voltage Intermittent