Where doesthe air for the heater/fresh air system come from?

230ina245 · May 14th, 2022, 20:56

Hi all,
Trying to find out where the air for the heater/fresh air system comes from.
Does anybody know the number and placement of the holes through the bulkhead that go from the area under the grill in front of the windscreen to the heater/fresh air system?
The Haynes is not very helpful here - hoping someone who has broken a 240 or at least removed the heater system may be able to help.
Tim

Clifford Pope · May 17th, 2022, 18:28

I have just had a look at the spare heater unit I removed from a car I dismantled.
All the air into the unit comes through the rectangular hole on the back, about 8" X 4". Inside the unit the various controls direct it to the different locations. Fresh air by-passes the heating element inside and passes directly to the fresh air vents. Heated air can be switched to screen, footwell etc.

The grill on the bonnet scuttle draws air into a void between the bulkhead as viewed from inside the car and that visible from the engine bay. It extends the whole width of the car and runs down behind the door pillars, draining rainwater out through the slot at the front 6" or so of the sill.

Some but not all models have a closeable vent to this drain at the sides of the footwell.

The system is both good, in allowing a generous passageway for leaves etc to get flushed out along with rain, but is also a weakness, because
a) It rusts the back of the rear face of the pillar where the hinges attach, unseen until the pillar collapses
b) The gap inside is partly formed simply from oiled cardboard, which decays letting in water, which runs onto the floor and then under the carpet, causing rust and also corrodes the fuses, which are carefully placed directly in the way!
c) If debris builds up water is directed inside the sills, which causes rust
d) Water leakage into the void from the wiper spindle seals and also the choke cable on carburettor models.

230ina245 · May 18th, 2022, 09:34

Thanks very much for this info.
Unfortunately, I have rust on the inside of my void and the seam that the bonnet seal attaches to.
From what you're saying I shouldn't have anything much behind the panel except for that 8" x 4" hole.
Time for some surgery I think.
Tim

May 14th, 2022, 20:56	#1
230ina245 Member Last Online: Yesterday 09:59 Join Date: Jul 2013 Location: Leics	Where doesthe air for the heater/fresh air system come from? Hi all, Trying to find out where the air for the heater/fresh air system comes from. Does anybody know the number and placement of the holes through the bulkhead that go from the area under the grill in front of the windscreen to the heater/fresh air system? The Haynes is not very helpful here - hoping someone who has broken a 240 or at least removed the heater system may be able to help. Tim

May 17th, 2022, 18:28	#2
Clifford Pope Not an expert but ... Last Online: Today 08:12 Join Date: Dec 2001 Location: Boncath	I have just had a look at the spare heater unit I removed from a car I dismantled. All the air into the unit comes through the rectangular hole on the back, about 8" X 4". Inside the unit the various controls direct it to the different locations. Fresh air by-passes the heating element inside and passes directly to the fresh air vents. Heated air can be switched to screen, footwell etc. The grill on the bonnet scuttle draws air into a void between the bulkhead as viewed from inside the car and that visible from the engine bay. It extends the whole width of the car and runs down behind the door pillars, draining rainwater out through the slot at the front 6" or so of the sill. Some but not all models have a closeable vent to this drain at the sides of the footwell. The system is both good, in allowing a generous passageway for leaves etc to get flushed out along with rain, but is also a weakness, because a) It rusts the back of the rear face of the pillar where the hinges attach, unseen until the pillar collapses b) The gap inside is partly formed simply from oiled cardboard, which decays letting in water, which runs onto the floor and then under the carpet, causing rust and also corrodes the fuses, which are carefully placed directly in the way! c) If debris builds up water is directed inside the sills, which causes rust d) Water leakage into the void from the wiper spindle seals and also the choke cable on carburettor models.

May 18th, 2022, 09:34	#3
230ina245 Member Last Online: Yesterday 09:59 Join Date: Jul 2013 Location: Leics	Thanks very much for this info. Unfortunately, I have rust on the inside of my void and the seam that the bonnet seal attaches to. From what you're saying I shouldn't have anything much behind the panel except for that 8" x 4" hole. Time for some surgery I think. Tim

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