Skoda Octavia 2018 1.6 diesel – having a few issues that no mechanic has been able to properly diagnose yet.

• Heater matrix not working properly
• Main issue: coolant warning keeps saying coolant needs topping up. When I refill it, the warning comes back again, and when I check the coolant tank it looks like it’s overflowing.
• Temperature gauge isn’t reaching 90°C, but the engine itself is getting hot.

Whats wrong

Sounds like an airlock somewhere but it could be a number of things or a combination. The coolant warning, if the coolant level is ok and it still persists try scraping the two prongs in the expansion tank. At the same time check that there is no silicone bag in there as they can burst and clog matrix etc. From memory the tank should have Mit Silicone on it if it has. The fact that its losing coolant and the tank seems to overflow may be due to a bad waterpump letting air into system or head gasket failure which is over pressurizing system. Check for air/exhaust bubbles in expansion tank with lid of and engine running. The fact that the temp isnt reaching 90deg could be a stuck/clogged thermostat.

Alasdair