On my Corsa C 1.2 52 plate the collant pipes dont get hot and the heater blow cold. I've replaced the thermostat but unable to remove the air lock. Any ideas thanks Steve.
Steve, take cap off expansion bottle while engine is cold, then run engine until normal temperature leave for 15-20 mins but keep an eye on coolant level, dont let it get too low, then just add water when needed. This should get rid of the air lock.
Take thermostat out and run at 3k rpm for a few mins. Gets the water circulating faster then pulling out any air locks and blockages.
Check 2 pipes going into the bulk head are equally warm and the same temp along the entire length. Sometimes the matrix gets blocked stopping the water circulation.