W210 Air Con.

[Ledbelly]

I have owned my 2002 E240 with 80k miles for nearly a year now.
The aircon didn't work at all when I got it and about 3 months ago I had it re-gassed after which it worked beautifully- ice cold.
That only lasted around 2-3 weeks so I assumed that I had a leak and was going to get around to getting it looked at.
A strange thing is now happening however. Every now and then, say once a week, the aircon will suddenly kick in and will often work until i stop the engine.
I have to say that when it does kick in it is not very cold but is definately well below ambient air temperature.
Does this sound like a sensor fault or something? I imagine that if i had lost the refrigerant again it would not work at all.
Any ideas gratefully received!

 

[bob6600]

Do you have the digital climate control? If so, you can run a diagnostic on the system. If could be something simple like a faulty sun sensor. If you don't have the digital climate control then perhaps a STAR diagnosis to see what is going on

 

[ChipChop]

Probably not the correct answer to your (leaky?) ac woes but the cabin air filter(s) make a huge difference on the w210 interior fan air flow. Try replacing them or remove them entirely to restore good air flow.

 

[alabbasi]

Check the pressure, row refrigerant or moisture in the system could cause the evaporator to freeze up

 

[ringway]

Check the pressure, row refrigerant or moisture in the system could cause the evaporator to freeze up

Let us hope it is not the evaporator. It is quite a job.

This was on a 210 owned by myself and Charles Morgan.



Given that it has actually been nice and cold, I think not the evaporator.
IIRC, when the evaporator dies, it doesn't get cold at all.

 

[alabbasi]

If the evap freezes up, it does not mean that it's the evap. A good set of gauges will tell you what's going on.

 

[MrGreedy]

When it does work, could this be because the ambient temp is high or car has been running or engine warm, as this might bring up the pressure enough to activate the pressure requirement in the system?

As in, you system had a leak, but can hold minimal pressure.

 

[Ledbelly]

Thanks for all the suggestions, I have plenty to think about now.
Looks like it might be worth getting the pressure checked and if that's ok I'll swap out the evap temp sensor, It's a cheap part and I might get lucky. I think a leak is probably the most likely problem although I did think that as I have some function it can't be leaking.
Mr Greedy's idea seems good.