Digital Heater query

[Greenmachine96]

Hi
2.5D R reg Bongo here.
No heat from heater, fans blowing, all linkages seem to move.
Engine temp on dashboard normally sits at 11 or 12oclock,no problems there. No recent coolant change.

Any ideas? I don't really understand what the digital controls do when changing temperature. Is there a hot cold mix happening somewhere?

Thanks

[g8dhe]

Yes there is a an air mixing box down central behind the dashboard, the fan under the bonnet blows the air thru the cooling matrix and into the box where there is a heater from the engine coolant. If the controls are working and the various control rods on both sides of the box are working, especially passenger side which controls the air flow over the heater (difficult to see hidden up high it adjusts a flap inside to put the air past the engine coolant radiator inside). Its not unknown for the heater matrix to get blocked and needs removing and cleaning or replacing. see these diagrams;
http://lushprojects.com/bongopartsmk2/c ... mgno=.html Mixing box
http://lushprojects.com/bongopartsmk2/c ... mgno=.html Fan under bonnet

[Greenmachine96]

That's brilliant. Exactly what I needed to point me in the right direction. I'll have a proper look and see what's happening in there.

[Greenmachine96]

The linkages are all moving as they should both sides. (In my head the digital display meant some sort of climate control, not just flaps opening!)

Could the thermostat have something to do with it. The temp control takes a while to wake up. Not sure timing exactly but it sits at cold for a good 10mins before moving to 11.

[g8dhe]

First if the Thermostat was stuck closed then you would find that you would be overheating, provided you took it for a decent run! If the the thermostat as stuck fully open then normally you will find that the temperature stays quite low even after a good run (greater than 20 minutes say). However if the thermostat is stuck part way then its more difficult to tell, just that it would take longer than normal (varies with engine, V6 takes 10 minutes on mine) for the temperature to rise to normal.
Check that the passenger side one is actually turning the shaft into the air box itself, I've seen ones where the shaft itself had broken before it entered the air box.

[Greenmachine96]

Thanks. I'll remove the covers and check it's all actually working. I assume fairly easy to do.

[g8dhe]

Yes drop out the glovebox, then worm up and under, cover as I recall is one maybe two screws then you can see if its actually rotating the spindle;
picture attached shows the one that snapped off!

[Greenmachine96]

Thanks Geoff. All seems fine, just not very hot. The car needs a coolant change, so perhaps a flush of the heater matrix is in order.