AC blowing cool but not cold

[RavzSa]

Hi All,


About a year ago I had the compressor replaced and the entire system flushed together with new drier and pressure switches. The AC had not been working for many years prior.


Ever since the replacement, the cabin will get cool but never cold. It doesn't matter on the outside temperate or whether its day or night.


I took the car back to the AC tech and they tested the system and could not find any faults. They advise that the pressures are all good and that the temperature at the vents measures between 8 and 10 degrees Celcius while standing idling. The pipe from the compressor to the evaporator gets coldish and sweats, and the condenser fan works as expected. The viscous fan is also working as it should be.


Today while on the highway at around 120kph I had the AC set to max. cold and then changed it up to 22. When changed to 22 the car suddenly started blowing colder and you could distinctly feel the colder air. I normally drive with the temp dials set to 22 and its not as cold as it got today.


Got home, switched off and restarted the car about 30min later, did not change any AC settings and once again it blew cool but not cold.


I assumed that when the temp dial is set to max cold the AC will run continuously and unregulated? Strange that the cabin became cooler whilst set to 22.


I've been monitoring the car and notice that the AC is always running when set to cold so I'm sure that it's not a faulty clutch. Note that the speed sensor has been overridden.


The drive belt has not been changed in a while, is it possible that the belt could be slipping although the belt shows no signs of fraying...?


Could it be the climate control unit? I felt the pipes to the duo-valve and it didn't feel like they had been energized...


I read somewhere that a faulty expansion valve could cause the same symptoms?


BTW, my fan switch is faulty and only works on speeds 2 and 3. I assume this won't affect the AC in any way though

[Chai]

The air-cond unit is working if the evaporator gets coldish and condensation drips off it.
If the unit suddenly gets colder when you adjust the temperature selection to a warmer setting, maybe the temperature control is turning the heater on.

Chai

[RavzSa]

I've been actually thinking the same but after a good run, the pipes to the duo-valves are not hot as the other coolant pipes.

Surely with the temp dial set to max. cold would disable the heater?

[Ivanerrol]

The temperature coming out of the vents should be colder than 8 - 10 Celsius. Last time I had a car done it was down to 2-3 Celsius.

[RavzSa]

This AC tech claims that 8-10 Celcius is excellent for an old car

I also was quoted for Denso compressor but after getting under the car I see they installed an "AC Edge" unit

Any experience with this brand?

I'm going to block off the duo-valve to check if it has any effect on the cooling

[Ivanerrol]

AC Edge seems to be a Sanden brand,
Although the one you have been supplied might be Chinese knockoff.

I have been down that route with an AC specialist. Quoted me one price to change a compressor and switch but installed a cheaper one “To save me money”.

The old “it’s just as good” doesn’t hold water if the specs aren’t the same.

If you were quoted a Denso (original equipment) you should have got one.

Changing a compressor is not that big a job if you have the altitude and even a little handy with the spanners.
I started doing my own changes for the simple reason I was making sure I installed the correctly specced equipment. Then I took the car to an AC specialist to be filled with gas and tested).

Allegedly the guides recommend that air coming out of the vent should be at least 20 degrees cooler than ambient temperature. (Providing the ambient temperature is not already quite cool).

[RavzSa]

These guys who fitted it are supposed to be the best in town

Been back there 3 times now and got the runaround. Going back this week to get my Denso compressor or refund

I measured the vents today and it was about 24 Celcius without ac and approx 14 with the ac.

Blocked off the pipes going to the duo-valves so definitely no "interference" from that

Considered doing the compressor myself and now I feel like I should have

[MMWA]

Properly functioning AC in my 124 freezes my hands and face if set too cold - Western Australia climate is similar to South Africa too and it has no issues with our summers.

I do all my own work with my own parts so i know what i've got. If i make a fk-up I own it as no one else to blame. avoid china crap where ever possible unless an absolute last resort.