Heater doesn't work after engine rebuild, possibly an air lock?

[striplar]

I've put a new head on my Fortwo passion MHD auto 999cc petrol Smart and the heater now doesn't work. I don't know if it was working before I bought the car but I assume it did.
Does anyone know of the procedure to purge air from the heater matrix?

[tolsen]

Be careful. You could easily need another head unless you bleed all air out of cooling system.

Bleed by disconnecting a cooling hose on left hand side of cylinder head near coolant temperature sensor Cap on expansion bottle must be off.
There is a description on how to bleed on page 40 of document "Introduction of the smart fortwo Model Series 451".

[Evilution]

http://www.evilution.co.uk/133

[striplar]

I already followed the instructions on the Evilution site and the car has had a good run. Do I take it that air locks in the heater matrix don't happen on the 451 then? I know it was an issue on the 450.

[BBE]

When you bleed the cylinder head, it is important to continue bleeding
until coolant escapes from both the head AND from the hose before
reconnecting the hose. I have done coolant replacement several times
and have never experienced any problem with the heater not working
afterwards.
Bjorn

[tolsen]

Heater matrix is bled automatically from expansion bottle. Just keep its cap off until all air is out. This is no rocket science. Air i bled off at the highest points similar to domestic central heating systems. That is expansion bottle and hose out of cylinder head on port side. Rapid changes in coolant level indicates there is still air in the system.

[striplar]

I'll pop the hose off again then and see if there's any more air to come out, but I doubt it. It's beginning to look like another issue, maybe the temperature control system? I've just come back from a 300mile motorway thrash and it's been fine but I'll certainly check it again. I think there's more on Evilution about the control system so I'll check that out if it's not an air lock. Clearly the cooling system is functioning pretty well and in that case I would have thought that the heater matrix must be filled with water.

[tolsen]

I suspect 300 chilly motorway miles.

I agree the problem may be elsewhere. Check coolant level and confirm return hose from heater matrix is hot. This hose connects at upper part of expansion bottle.

[striplar]

Chilly is an understatement, it was sub zero all the way and I wrapped my legs in bubble wrap I happened to have in the car to stave off frostbite.... That sounds like a good plan. I'll check that return water temperature. I've found the relevant Evilution pages on the subject of the control system and am digesting that too. Sometimes I can't help but think we were better off with mechanical levers and flaps to direct the heat.