The missing coolant

[PK1]

I did a coolant change in my M-Coupe yesterday and drained both the radiator and the engine block using the process exactly as laid out in TIS and also reading up on forums. It seems most people get 7.5-8 liters of coolant out through this process. Sure enough, I got about the same and used about 8 liters to fill the system, +/- 0.5 liter or so wasted during the bleeding process.

If the total system capacity is 10.7 liters (if this is wrong please confirm), then 2-3 liters of old coolant stays in the system even when draining the engine block, so it's not a complete drain. Where does the remaining coolant stay in the system? Hoses, etc.?

[Terraphantm]

Heater core maybe?

[PK1]

Possibly, but looking at the parts diagram of the heater core, it seems that the coolant should be able to drain on the lower port - assuming that the engine block drain location is lower than the lower port of the heater core, which is hard to assess from the diagram.

[rsutoratosu]

Probably if you leave the drain open and you use the pressure kit to pump air in.. itll come out

[Terraphantm]

Originally Posted by PK1

Possibly, but looking at the parts diagram of the heater core, it seems that the coolant should be able to drain on the lower port - assuming that the engine block drain location is lower than the lower port of the heater core, which is hard to assess from the diagram.

That would be assuming the heater core valve is open, right?

[PK1]

Yep, heat setting to high and fan on.