A.C....not very cold. - Alfa Romeo Forum
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A.C....not very cold.

The AC in my 2.0 JTDm is not very cold...it's gets the car coolish....but not freezing like all the other cars I've owned with AC. The wife's Merc A170 is so cold it's almost unbearable on "Lo". So her car gets cold almost instantly, even after standing in the sun all day...mine takes a few minutes. I noticed from the history that there was no mention of an AC refrigerant change...so I got it done. Passed the vacuum test and pressure test with flying colours. Not much had been lost over the years..well within tolerances. The car is definitely cooler than it was...a bit...but still does not give you that "ice cold face" feeling that I believe all aircon should. Or is it just like that on 159s? Any ideas? Thanks in advance.
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(Post Link) post #2 of 15 Old 1 Week Ago
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How much gas did you put in?
I wasnt able to find out the correct amount for 2.0 diesel.
For 1.9 diesel there are two options - 460 g or 550 g depending on the type of compressor but nothing for 2.0 :/
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It gets very cold in mine, so it sounds like something is wrong.

I don't want to insult your intelligence by asking if all the vents are open and facing in the right direction
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Have you changed the pollen filter?
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Member car:

159ti 2.4JTDm

I have to admit, I don't find mine all that cold, certainly not as cold as my 147 was - also, I find the fans a bit urgent, there's never a comfortable setting between too much air and enough.

Mine was re-gassed last year, all vacuum tests fine, and new pollen filter about 4 months ago
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I think the 159 icapacity is not very large by design. I noticed it also has little effect on driving economics (meaning AC on is quite economical). I think it is just system design. Never had the freezing cold air I used to have in my BMW or Lancia, but I feel the cooling and dehumidifying are much more comfortable. I agree with you that it won't cool down the entire car in under 1 minute, but then again I don't need it to.
Any AC system that can cool a cabin from 50C+ (sitting in the sun temp) to 20C without opening the doors or windows is over dimensioned.
Maybe the doors on the merc are bigger, letting out more hot air in whilst you get in?

AC basics, there are 3 factors that influence the cooling of the AC:

1 System chilling capacity:
How much can it cool? It might be that the alfa just has lower capacity by design, because for example better economics, system physical size or just the cost of the whole thing. The performance is limited by the capacity of the compressor, evaporator and condensor. Thats the design capacity assumming it is brand new and configured correctly. This can change over time, if the system is not well maintained. If this is the cause, it can be solved by re-gassing the system.

2 Airflow
How much air goes through? Can all the "coolness" be transferred to the air? or is the delta temperature between the evaporator and surrounding temperature too low?(the higher the temperature delta the more "coolness" (or heat, the other way around) is transferred in the same amount of time. This can be affected by wrong settings on the "dials" (wrong channels or low fan speed settings) or a clogged up pollen filter (the cooling system is breathing through a straw).

3 Intake air.
The system is not limited to an actual temperature (e.g. 16C) but a relative temperature. For example; it can cool the air temperature by 7C in 1 pass. This is also affected by humidity (since moist air is harder to cool, since you lose some "cool-power" that is used to condens the water) and how close that temperature is too freezing of the coolant. This is why automatic systems switch on re-circulation when the delta between outside temp and desired temp is too high. It cools the air in the cabin for a second time, to reach a bigger temperature delta to the outside temperature, and to increase efficiency since the air in the cabin is already dehumidified..

First thing to do is check if you're having issues with the alfa "used to being just as good and is now worse" or the merc just being better by design.
- The systems may have a different design capacity. Maybe Merc has fitted a better compressor or evaporator at the cost of space or power consumption. Not all AC's are created equal.
- Compare the settings with the merc (e.g. are they both at max fan speed and re-circulation?)
- make sure both systems are well maintained (when was the system re-gassed and pollen filters changed last?)

This applies to all heating and cooling systems. Now you know how it works I think you can diagnose what's wrong.

Last edited by kid1988; 1 Week Ago at 09:22.
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(Post Link) post #7 of 15 Old 1 Week Ago
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My compressor failed earlier this year, but did gradually decrease in efficiency, there is a thread somewhere about checking the compressor clutch which might be worth a go?!


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Could it simply need a re-gas? Groupon have a deal at the mo for Kwik-Fit. Don't usually like using these places but for A/C recharge at £30 it seemed too good to miss. Booked in for Sat
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I had a similar problem on my Kia I had, got it re-gassed still didn't work even though it passed the vac test turned I the replaced the compressor and it worked for a year or so then the new compressor stopped working/burned out turns out there was a very tiny leak in the A/C rad that only really started to leak in the hot weather through expansion so it might be worth checking both the compressor to see it its working and also checking the rad for any leaks
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P.S. I now own a 159 myself and the A/C works a treat so I dont think it's just a case of the 159's A/C not being very efficient in general
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That's for that advice. It was regassed a couple of months back. I don't know the amount...it was done by my local AC specialist...he just typed in the VIN and the machine did the rest. It was colder after...but not as cold as my previous cars...acceptable...just not brilliant. Pollen filter was changed at roughly the same time. Deff no leaks...it held the vacuum and pressure test with no issues. Guess I just live worth it until something breaks!
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If gas is good I would say either compressor is weak losing pressure internally or the TEV is not performing correctly. My 159 was the same worked but not as well as should be. The TEV on mine was the problem never actually replaced it as I sold the car.
A decent air con place will hook the gauges up and be able to see what’s going on
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Did you read-out the ECU (of the CC system)?
They’re prone to go broken on the air temperature sensor for the cabin room. If so, it will store a DTC.
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I had problems with the Aircon on my 2011 2.0 JTDm, the double pipe from the compressor leaked, the pressure sensor failed as did the control that fits behind the radiator. Even when these were all changed and recharged it still didn't work.

I then took the car to a specialist (non-Alfa) who recharged it with a greater volume of gas - it then worked and is very cold!

Apparently some 159s have a greater volume of gas than others.
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From the info I can find my car should have 460ml....and thats what it had....as far as I can remember....cant find the AC machine printout right now!!.
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