MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - AC extra fan

Hi...
BKK is extremely hot in the summer...reaching 40c. Wonder by adding extra fan, will this help with A/C in the car.

Any other solution otherwise.

Hot Hot Hot.
Thanks
Hank
hank teekaveerakit

Hank,
Do you have a Black SofTop up at the same time ?? If so,the black absorbs the heat to make the car hot so that it is fighting the AC.
I fitted a Silver HardTop which reflects the heat so the AC only cools the driver.
Geoff F.
G. Farthing

Hank

All A/c equipped cars come with two radiator mounted cooling fans, perhaps your system needs recharging.


Tony
Tony H

Hank,
Can you check with any other owners locally to see if they have the same problem ?

I believe that the cars were heat tested in the Nevada desert, I have seen photos taken in Death Valley, Nevada.

When I was last there in 2002 the temperature was 131 degrees F in the afternoon sun( about 55-56 degrees C)although bear in mind the humidity level is next to nothing, so maybe your high humidity could cause you a problem.

As Geoff rightly says black will definitely not help.

I wonder though, did the test cars have A/C back in 94/95 ?

Adrian
Adrian Clifford

Hank, do you mean an extra ventilation fan?
Rob Bell

Hank,
What I understand from your initial thread is that your airconditioning is not cooling down the inside of your car enough or to your satisfaction.

This may be due (as Tony said) to the airconditioning system needing a gas top up as it may have a very slow leak.
If you have a digital thermometer, then test the air temp just inside the centre vent with all the other vents closed and the cabin fan on full and aircon on.
It should be around 8-12'C
If not, get it checked out by an aircon service centre.

Some receiver/dryers have a little sight glass window that you can see into. When the aircon is on, look in the sight glass and if there are bubbles flowing around, then you will need the system evacuated and regased. But I'm not sure if these have such a window.

HTH
Branko.
Branko

Well it can get warm over here and with high humidity. Mid 40's and 80% and I find the A/C copes very well, with the recirculating button activated and the roof up!. As Rob states the car has two fans and check the freon gas levels. Don't forget the unit can be used all year round by turning the heater on with the A/C it also dehumidifiy's the interior and the windows won't fog up in fact the only time I don't use the A/C is if I drive a car with the top down.
Andrew Regens

I think it's also a good idea even in winter to run your aircon for about 10 mins every 2 weeks as this will lubricate all the rubber seals in the system. If you don't these seals may dry up and crack causing gas leakage.

Just a small point, (Andrew, hope you don't mind) the old type of gas was called "freon" which was a refrigerant gas actually named R12 and contained CFC's (chlorofluorocarbons). Not very Ozone friendly.
Since about 91-92 most car aircons had been manufactured to use 134A gas which is ozone friendly and does not contain CFC's. Thats what the MGF's use.

Unfortunately the 134A gas is not as efficient in its cooling actions as the R12 gas was.
But whats a couple of degrees here or there when it comes to our environment. Right!

Cheers,
Branko.






Branko

Dear all good friends

In actual fact my a/c works fine, but with the heat over hear it does not have enough power to cool it down.

on extra fan, some mechanical guy suggests that this extra fan help cooling the condenscer.

I have hard top black color.

Now thinking about changing the more powerful, compressor.

hope enough infor. provided, that way i will not be misleading anyone.

any thoughts.
thanks
hank
hank teekaveerakit

Hank,

As already mentioned, you may need an expert aircon person to test your system. Maybe with the help of "some mechanical guy" :-)

Here is some info from the workshop manual that may be of some help.

The two cooling fans are controlled by the ECM and
dependent upon engine coolant temperature and air
conditioning system pressure. With the air
conditioning system switched off, the (radiator)
cooling fans are operated with the ECM controlling
the fan speed according to engine temperature. With
the air conditioning system switched on, condenser
(radiator) cooling fans are connected in series by the
ECM and operate at low speed. As the pressure of
the air conditioning refrigerant rises above the
threshold of the medium pressure setting on the
trinary pressure switch, the cooling fans are
connected in parallel and operate at high speed.


Performance Guide-lines
Carry out this test with bonnet, doors or windows
open; air conditioning switched on, temperature
control set to cold, face vent mode and blower at
maximum speed. Set the air supply control to supply
fresh air.
1. Close low pressure valve on Refrigerant
Station.
2. Close high pressure valve on Refrigerant
Station.
3. Connect Refrigerant Station to the high and
low pressure servicing connections.
4. With a thermometer measure the air intake
temperature, close to the outside air inlet at the
plenum.
5. With a thermometer measure the air outlet
temperature, at the centre vent outlet.
6. Run the engine at idle speed for 10 minutes or
until normal operating temperature is reached.
7. Read both pressure gauges and
thermometers. Check readings against the
guide-lines shown in the table below.

Ambient 20C 25C 30C 35C 40C
Outlet Temperature (C) 5 - 10 7 - 15 8 - 20 11 - 22 14 - 25
Low Pressure (bar) 1.6 - 2.4 1.8 - 2.6 2.0 - 3.2 2.2 - 3.5 2.4 - 3.8
High Pressure (bar) 14 - 19 14 - 19 14 - 21 18 - 23 19.6 - 24.8
Notes A +B A+B A +B B B

NOTES
The temperatures and pressures may be slightly
increased for high humidity conditions.
The varying air conditioner pressure will dictate
whether the fans operate in series or parallel,
which will itself cause the temperatures and
pressures to fluctuate. For example:
A =Condenser and cooling fan both running at
half speed (series)
B =Condenser and cooling fan both running at
full speed (parallel)
A +B =Fans switching from series to parallel.


This testing needs special equipment and expertise.

I would suspect that you system needs attention.

Cheers,
Branko.

Branko

Mind you Branko, I suspect that Hank could be right: the standard fit aircon, even if in tip-top condition, may not be man enough for the job under circumstances of extreme warmth and humidity.

Hank, good luck, but I personally can't proffer any help - I've got no experience with aircon, and I don't have any ideas on how to improve its performance over increasing the condensor radiator's size and capacity, fitting a more efficicent fan, and looking into changing the compressor itself.

Do keep us posted as to your progress though! :o)
Rob Bell

Rob, you may be right.

Be aware that the cooling capacity is dependant directly on (but not only) on the compression value of the compressor.
Some are 8.5 and other are at 9.0 or 10.0 etc.
(can't remeber the units though)

Maybe an upgraded compressor is needed. ?
I once installed a new compressor in my wifes Volvo 240 and the new compressor was not rated as high as the original I took out.
The aircon worked OK by was never as cold as what the original used to be when it was working.


Cheers,
Branko.
Branko

This thread was discussed between 25/04/2005 and 30/04/2005

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.