Hello all. 

Do any of you guys have any experience with the Mk4 Focus? 

I have a 20 reg ST Line with the manual aircon and the issue I have is that when running without aircon on, the temperature of the air coming through the vents on cold is always warmer than the outside temp by 6-10 degrees Celsius. 

Ok,  this doesn't sound a lot, but I just want cool air on my face,  not too dissimilar to the outside air temp. 

The issue appears worse in hot restarts. 

Its like the air picks up some heat from somewhere under the dash. 

The removal of the cabin filter makes no difference. 

I would argue the air conditioning should be cooler too. 

The dealers have suggested a possible heater flap issue,  however they can't inspect the vehicle for a few weeks. 

Does anyone have any similar experience? 

Thanks 

I’ve got exactly the same problem on my ST Line X with 1.0 mhev. 
 

Did you ever find a solution?

Why not just use the air con if you want cool air?

The air intakes for the cabin are at the bottom of the windscreen tucked under the edge of the bonnet, of course it’s going to pickup some heat from the engine especially on hot restarts as it will heat soak quite a bit. 

I've not long had my Ford Focus, and the weather turning cooler has revealed this same problem. Outside air temp was 15C, controls set to "LO", air-con off, and the air coming through the vents was at 24C-26C, despite the interior of the car being around 20C.  Put on the air-con, and that flow temp. dropped to 12C.

I really shouldn't have to burn extra petrol to run the air-con when it's only 15C outside.

Is this a sign of bad design, such that the incoming air always runs over hot areas, or is there design fault in the components that control the routing of the air, such that they fail?  Or, is there some simple fix that I've missed?

Andrew

The system is called Air Conditioning not Air Cooling. You set a temperature (eg. 20C) and leave it on in the automatic mode. It is designed to operate all year round not just in the summer. 

4 hours ago, First_time_Ford_owner said:

I've not long had my Ford Focus, and the weather turning cooler has revealed this same problem. Outside air temp was 15C, controls set to "LO", air-con off, and the air coming through the vents was at 24C-26C, despite the interior of the car being around 20C.  Put on the air-con, and that flow temp. dropped to 12C.

I really shouldn't have to burn extra petrol to run the air-con when it's only 15C outside.

Is this a sign of bad design, such that the incoming air always runs over hot areas, or is there design fault in the components that control the routing of the air, such that they fail?  Or, is there some simple fix that I've missed?

Andrew

Open a window?

1 minute ago, alexp999 said:

Open a window?

I tried that.  It lets in noise of other traffic (and one of the things I like about the car is how quiet it is inside), and there are some astonishing Helmholtz resonator effects, which make it unbearable at some speeds. 

The air circulation is not the same as it would be through the face and foot vents, so it's not a substitute anyway.

 

6 minutes ago, unofix said:

The system is called Air Conditioning not Air Cooling. You set a temperature (eg. 20C) and leave it on in the automatic mode. It is designed to operate all year round not just in the summer. 

It's called Air Conditioning, not Air Warming 🙂 .  I simply want fresh air coming in through the vents, without it being significantly heated on the way.  Every other car I've ever owned or rented has been able to manage that, whether they've had A/C or not.

If the air is unavoidably warmed on its way in, and so has to be refrigerated by running the compressor etc., than that's inefficient.

What people seem to be saying is that this is not a fault - it's the way the car has been designed and built.  It give the appearance of being sub-optimal.

2 minutes ago, First_time_Ford_owner said:

What people seem to be saying is that this is not a fault

Correct.

I don't know the answer to your question because my Focus has Automatic Climate Control but I can sympathise with your problem if it is designed like that.

My last Rover car would let you have completely uncooled air to your face irrespective of where the Heater controls were if you wanted it and the the Airflow through all the vents with the Fan off was very good while  driving, the Focus airflow is almost non-existent unless forced.

And yes the Resonance with the windows open is very loud, especially the back ones.

My first Ford (Mk 1 Cortina) had the "airflow" ventilation system which was very efficient, and let you have cool air on your face and warm air down below, with a good flow of air without needing the fan (as long as you were moving, of course). So much for progress.

In every car I've had with aircon (whether manual of automatic) I keep aircon on 100% of the time. In a car with ACC I just set my preferred temperature when I get the car, press "auto" and never touch it again.

With manual a/c, I adjust to whatever I require on any particular day.

Never found leaving it on had any noticeable effect on mpg.

As John mentions, most modern cars have little or no airflow unless the fan is set to operate.

I wonder if the reason there is little natural airflow in modern cars is so that the HVAC design can be dumbed down because of the reduced number of air changes.

On the subject of Aircon, I do keep my Climate Control on all the time but I'm not sure that air with little humidity is good for you all the time.

When my partner got Altitude sickness on a high altitude Skiing holiday the doctor prescribed an Oxygen  machine for the hotel room and told to us ask reception for a Humidifier as well. They had plenty so there must be a reason for them having them.

I'm sure professional singers inhale steam as well to keep things working correctly.

3 hours ago, unofix said:

3 hours ago, First_time_Ford_owner said:

What people seem to be saying is that this is not a fault

Correct.

Therefore it's a design choice, but a peculiar one.  Perhaps someone who knows how and why that choice was made can explain it.

28 minutes ago, Tizer said:

I wonder if the reason there is little natural airflow in modern cars is so that the HVAC design can be dumbed down because of the reduced number of air changes.

On the subject of Aircon, I do keep my Climate Control on all the time but I'm not sure that air with little humidity is good for you all the time.

When my partner got Altitude sickness on a high altitude Skiing holiday the doctor prescribed an Oxygen  machine for the hotel room and told to us ask reception for a Humidifier as well. They had plenty so there must be a reason for them having them.

I'm sure professional singers inhale steam as well to keep things working correctly.

Dry air is not a problem in the UK it’s a generally damp country. They were told to get a humidifier because the air becomes very dry when there is snow and the lungs don’t work as efficiently if they dry out. I regularly visit my friends in Norway and coming back to the UK is like swamp air in comparison 

51 minutes ago, First_time_Ford_owner said:

Therefore it's a design choice, but a peculiar one.  Perhaps someone who knows how and why that choice was made can explain it.

The whole HVAC box including heater matrix, AC evaporator, electric heater element and all the diverter flaps have to be fitted in a very small space.  I doubt there's much 'choice' in the design, it's more like just cram it in wherever it fits!

This does seem like an odd issue though.  Unlike others I never run AC unless it's hot out and have never had this issue on any other car.  Admittedly I only drive it 100 miles but I didn't notice my own Mk4 having this problem.  That said, it has a panoramic roof which makes the interior disgustingly hot from the smallest ray of sunlight so maybe not the best comparison.

1 hour ago, alexp999 said:

Dry air is not a problem in the UK it’s a generally damp country. They were told to get a humidifier because the air becomes very dry when there is snow and the lungs don’t work as efficiently if they dry out. I regularly visit my friends in Norway and coming back to the UK is like swamp air in comparison 

That is correct, the point I was trying to make is that running Aircon dries out the air, so running it all the time might not be as good for you as breathing in outside air via an old style car ventilation system especially if you have permanent or temporary health problems.

That doesn't mean I think running your Aircon will make an otherwise healthy person ill.

The UK is a humid country, more so inside occupied houses. I used to have to do Interstitial Condensation calculations back in the days when they were done with a pen, paper and calculator.

Taking my 2021 Focus st-line X Edition back to Trustford as the A/C has gone back to blowing warm air again. Their last answer (2 days ago) was that the battery needed to be charged overnight, they did this and upon receiving it it was a bit cool but not cold as I’m used to with other Fords. Anyway it’s blowing warm air now and it’s courtesy car time tomorrow. The plot thickens.

The AC on a MHEV is never as cold as on a traditional engine. Oddly they do require a good fully charged battery to work.

Taking my 2021 Focus st-line X Edition back to Trustford as the A/C has gone back to blowing warm air again. Their last answer (2 days ago) was that the battery needed to be charged overnight, they did this and upon receiving it it was a bit cool but not cold as I’m used to with other Fords. Anyway it’s blowing warm air now and it’s courtesy car time tomorrow. The plot thickens.

When I first got it a week ago it put ice on the windscreen, then after a while it went to blowing warm air.

When I first got it a week ago it put ice on the windscreen, then after a while it went to blowing warm air.

UPDATE.

 

Friday, just got it back now, turns out it was a TCU update was required. Now cold enough for a Polar bear.

Hi sorry to resurrect this thread, but having the same problem and local garages can't seem to identify the issue. Simply said that software calibration or reprogramming is needed...

Is a TCU update something that a layperson can do or must it be done at a garage?

 

Hi Jason, 

Does the AC compressor engage? Can you hear the "click" sound when you push the A/C button.

If not, then most likely either your 12V battery SOC has dropped below 50%, or the AC gas pressure is low. Could be some mechanical failure at the compressor, but I haven't really heard of any happening to 5 year old Fords.

Cheers!

Hello Jason

 

Further to RaduF86 reply to you.

 

I had similar AC problem.

AC pressure checked/refilled - OK. Garage did it for free because it didn't solve the problem.  Good lads.

Compressor was not engaging on hot days.

I replaced the high pressure sensor (about £18).  Part number printed (small) on the sensor.

It's on a a self sealer valve and easy to get to so straight forward process.

Open the bonnet (Focus Mk4), look down to the left, engine side of the radiator is a small bore aluminum tube with sensor screwed in. 

 

I looked at that because the AC compressor clutch was intermittent, would activate on colder days but not during the heatwave.

So I suspected fault was that sensor because it would not run for long - due to pressure increase perhaps.

It did make me smile - AC worked on cold but not hot days.

 

Hope this helps.