Hi new to the forum just got myself a e91 335d wanted to find out had to drain my coolant as had a leak sorted the leak out got two ? That waned to ask on my water bottle am I meant to see a return all the time if the caps off like is it meant to flow with water out the return to the Bottle all the time as even when thermostat is open don’t get a return till I press the throttle like it’s not continuously coming out the return pipe hole to the water tank it don’t over heat I thought there was air inside as didn’t get constant return so drained it again and used a coolant bleed and refill kit that sucks all the air out the replaces it with coolant so no air gets in and still no return wanted to as another 335d owner my big coolant pipe that goes under the intake manifold to we’re the glow plug module is located seems really hard harder then the rest all pipes are hot on the car and heating inside the car just wanted to see if another 335 d owner can check when it’s up to temp is there pipe really hard mine just seems to hard but didn’t no if that’s how they are sorry for long post hope someone can help
