David Mills
12-06-2008, 17:03
OK so I have found the draft data and it's pretty basic, but might be of some help
Checking Hot/Cold Cabin Temperature Linkage
Control of the temperature in the MGF is a little basic, but when working, very effective. Unlike many other modern cars, the ‘F’ controls the amount of hot water entering the heater matrix, rather than allowing water to circulate the matrix always, and then controlling the amount of hot air exiting.
To achieve temperature control, the Hot/Cold knob is linked to a valve via a Bowden cable connected to a series of Heath Robinson designed metal links and plastic cams. These links attempt to translate circular motion in one plane to a rotation in a perpendicular plane. In other words, if you look at the dash (see photo MGF_DJM_8), turning the central knob left or right, actually moves the valve control towards or away from you.
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_8.jpg
With this set up there are two primary faults, which can occur.
Mechanical Linkage problems – generally caused by components to becoming detached from one another, preventing the valve from being adjusted.
Valve problems – valve failure or air locks in the cooling system preventing the valve from functioning correctly.
The first is usually obvious and can be checked and fixed using the script below. The second is a bit more tricky and could become expensive.
Difficulty : Easy, suitable for a novice
Duration : Checking will take approximately 5 mins.
Tools Required : cross-head screwdriver
Process :
Access to the linkage is gained via the driver’s footwell. (See photo MGF_DJM_9).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_9.jpg
Unscrew the two Phillips screws holding the plastic panel with the footwell light and remove (see photo MGF_DJM_10).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_10.jpg
The valve control mechanism can then clearly be seen (see photo MGF_DJM_12). It is controlled by the Bowden cable (Red sheathing) which connects to the metal and plastic cam linkages.
Turn the heater control fully to the hot scale and the linkage should move to the position in the photo (MGF_DJM_12).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_12.jpg
Then turn the control fully to the cold end of the scale. You should see the Bowden cable move and swing the metal link in the plastic camplate eventually moving the valve, leaving the mechanism as shown in photo (MGF_DJM_13).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_13.jpg
Whilst turning the heater control it should be obvious if any part of the mechanism is not moving, including the valve.
If the cable is not moving then check that the Bowden cable has not become disconnected at either end. To check the control end, prize off the heater knob and view from the front of the dash.
If the cable moves, but the plastic camplate does not then the metal linkage has probably just been dislodged from the slot in the camplate.
Check also that the valve control does move.
If all parts are moving, then it is possible that the valve has become blocked or damaged or that there are air locks in the system. This is a lot more tricky to diagnose and repair. If you are a novice it might be time to get the experts involved. If you are an expert, then it is time you contributed to the FAQ and provided some more detail to this very simple check script.
In true Haynes style, Replacement is the reverse of removal.
Grainy Photos to come shortly
Checking Hot/Cold Cabin Temperature Linkage
Control of the temperature in the MGF is a little basic, but when working, very effective. Unlike many other modern cars, the ‘F’ controls the amount of hot water entering the heater matrix, rather than allowing water to circulate the matrix always, and then controlling the amount of hot air exiting.
To achieve temperature control, the Hot/Cold knob is linked to a valve via a Bowden cable connected to a series of Heath Robinson designed metal links and plastic cams. These links attempt to translate circular motion in one plane to a rotation in a perpendicular plane. In other words, if you look at the dash (see photo MGF_DJM_8), turning the central knob left or right, actually moves the valve control towards or away from you.
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_8.jpg
With this set up there are two primary faults, which can occur.
Mechanical Linkage problems – generally caused by components to becoming detached from one another, preventing the valve from being adjusted.
Valve problems – valve failure or air locks in the cooling system preventing the valve from functioning correctly.
The first is usually obvious and can be checked and fixed using the script below. The second is a bit more tricky and could become expensive.
Difficulty : Easy, suitable for a novice
Duration : Checking will take approximately 5 mins.
Tools Required : cross-head screwdriver
Process :
Access to the linkage is gained via the driver’s footwell. (See photo MGF_DJM_9).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_9.jpg
Unscrew the two Phillips screws holding the plastic panel with the footwell light and remove (see photo MGF_DJM_10).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_10.jpg
The valve control mechanism can then clearly be seen (see photo MGF_DJM_12). It is controlled by the Bowden cable (Red sheathing) which connects to the metal and plastic cam linkages.
Turn the heater control fully to the hot scale and the linkage should move to the position in the photo (MGF_DJM_12).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_12.jpg
Then turn the control fully to the cold end of the scale. You should see the Bowden cable move and swing the metal link in the plastic camplate eventually moving the valve, leaving the mechanism as shown in photo (MGF_DJM_13).
http://i145.photobucket.com/albums/r202/MGTFDJM/MG%20Cars/MGF_DJM_13.jpg
Whilst turning the heater control it should be obvious if any part of the mechanism is not moving, including the valve.
If the cable is not moving then check that the Bowden cable has not become disconnected at either end. To check the control end, prize off the heater knob and view from the front of the dash.
If the cable moves, but the plastic camplate does not then the metal linkage has probably just been dislodged from the slot in the camplate.
Check also that the valve control does move.
If all parts are moving, then it is possible that the valve has become blocked or damaged or that there are air locks in the system. This is a lot more tricky to diagnose and repair. If you are a novice it might be time to get the experts involved. If you are an expert, then it is time you contributed to the FAQ and provided some more detail to this very simple check script.
In true Haynes style, Replacement is the reverse of removal.
Grainy Photos to come shortly