Mondeo air con

[RonD]

I have an 18 month old Mondeo TDCi 130, the only problem I have is the air con. Should the main radiator fan run when the aircon is switched on? Aircon seems OK when moving at speed but in traffic the cooling doesn't work at all. When it's on I can hear the compressor cycling on and off every 5 seconds or so. I've had the system regassed recently. The regasser told me the 'fan' is not working...what fan? Any ideas?

Ron

 

[Royston]

Hi Ron D

When using the aircon I always have selected internal air and the main blower on the second setting, you have given me food for thought as I have never thought of a fan in the air con system.

Royston

 

[ProfJohnL]

Hello Ron,

The obvious answer is to ask your AC engineer which fan?

I am not familiar with the Mondeo system, but all AC units have two coils, just like a fridge, one inside and one outside. The coils are heat exchangers, and if the external one ( the Condenser) coil is mounted in a recessed area it may need fan assisted air to operate. Some systems mount the condenser near the main cooling radiator and use the air flow from the main fan, but others may need an additional fan.

In my Saab 93, the main cooling radiator fans cycle quite frequently even at idle when the AC is turned on.

 

[RonD]

Thanks for your comments Royston & John...

Regards,

Ron D

 

[John_374353318]

As John L says there are two heat exchangers in an AC system. One inside the car, the evaporator, fitted inside the heating/cooling/ventilation system and the other, the condenser, fitted within the engine compartment, usually in front of the engine cooling radiator. AC systems are a sealed system, refrigerant gas is pumped at high pressure through the condenser which takes out the heat caused by the compression and turns the gas to a liquid. Because of the amount of cooling required, in most cars, the engine cooling fan/s run constantly whilst the AC is switched on.

The now cold liquid, still pressurised, is forced via a small jet into the evaporator which reduces it's pressure and turns some of the liquid back to a gas. At low pressure the liquid refrigerant is unstable and wants to return to a gas, to do this it takes heat from inside the car. The blower fan is used to force air through the evaporator matrix into the interior ventilation system so cooling the interior of the car.

From the evaporator the gas is returned to the pump to start the cycle again.

I sugest that the fan which is not working is the blower fan, inside the car. Whilst you are driving air is forced through the ventilation system by the forward movement of the car. Whilst standing no air is moved through unless the blower fan is working, which yours appears not to be. The blower fan motor it's self may not be at fault it could be in the wiring or switching as there are often two seperate electrical circuits controlling heating and cooling, although some parts are common to both.

I sugest you seek the advice of a Ford dealer as I assume, at only 18 months old, the car would still be covered by the Ford warranty.

John

 

[RonD]

Thanks John,

The tech that regassed the system showed me that if he cooled the front radiator area of the car with a hosepipe the aircon worked well whilst stationary. He explained he wasn't an autoelectrician and I needed to see one to resolve the fan problem which you have described. This fan is nothing to do with the heater fan then? Is it separate? The big radiator fan doesn't run when the aircon's on but I assume it does when the engine temperature rises? (I've spoken to my Ford dealer and the first thing they will do is regass the system, which it doesn't need, at a cost of

 

[Glenn_5132962]

The fan that has failed is the one for the aircon radiator (condensor) at the front of the car. That radiator needs cooling air for it to dissipate its heat. When the car is moving it gets the cooling air forced through it. With the car stopped it needs a fan to suck air through it. If the fans not working then there is no cooling. Thats why it worked when the tech sprayed water at it - it got the cooling it needed.

 

[RonD]

Thanks for the info Glenn... this is what the regasser told me. Where is this fan? What am I looking for? Is it under the main radiator fan? Should the main radiator fan run when aircon is on, irrespective of engine temperature? I've checked all fuses with a 'fan' symbol and all seem OK. I'm wondering whether something's been disturbed by the towball fitter whilst running his 12v and ignition feeds through the front?

Regards,

Ron

 

[butler1]

Ron, As your car is still under warranty can't you just take it back and ask them (Ford) to get it fixed? Quite frankly, the last thing I want to hear are technical details when all I want is that icey blast on demand. When it's fixed just remember to use the aircon for five minutes every month whether you need it or not. Apparently it keeps the system pressurised.

 

[RonD]

Ron, As your car is still under warranty can't you just take it back and ask them (Ford) to get it fixed? Quite frankly, the last thing I want to hear are technical details when all I want is that icey blast on demand. When it's fixed just remember to use the aircon for five minutes every month whether you need it or not. Apparently it keeps the system pressurised.

I understand what you're saying Butler, but...I've spoken to the Ford dealer who say their standard policy is to regass the system, add some dye to check for leaks and then take it from there. That will cost me a minimum of

 

[ProfJohnL]

Hello again Ron,

A little more of the story has unfurled.

I assume that prior to the towbar being fitted, you were unaware of a problem with the AC. Did it work when stationary? (I should add that most do work when stationary)

So if the problem coincided with the fitting of the towbar then it is highly likely that it may be something to do with the towbar electrics

Solution - Tell you towbar fitter about the problem, and the fact that an independent AC technician has identified a problem that occurred following the fitting of the towbar. Ask them to check their fitting and wiring.

Ask them to confirm that the fitting and connection points they used are the ones recommended by Ford for your model of car. If not ask them to refit according to Fords schedule under their fitting warranty. (Sale of Goods and Supply Services Act)

If they wont play ball, talk to Trading Standards, as your fitter has supplied goods or services that are not fit for purpose.