Hi
2004 TD4
In an attempt to get my A/C working, I've had a new condenser fitted as it had a small leak, once it was working there was a noticeable load on the engine when the A/C was turned on (normal) and a slight belt squeak for the compressor which told me it was working.
After a few weeks it stopped working and I found a pinhole leak in a pipe so replaced that and re-gassed and pressure tested ok, but now it doesn't seem to put any load on the engine when turned on, I had my mobile aircon guy come and check it again and he confirmed the gas was still ok and holding pressure.
The 2 AC pipes under the bonnet are cold and warm so something is happening but I'm not convinced it's working as it should due to no load when engaged, the aircon guy said he could see the compressor clutch engaging when I pressed the button but the revs don't drop at all whereas they used to.
I spoke with a FL specialist and he said it could be because I've fitted a new battery as the AC draws 30 amps but it was doing it before I changed the battery.
There's no point feeling the air temp as the general air outside is still cold.
I also noticed water dripping out of the AC pipe under the car but the AC wasn't turned on, is this normal?
Any thoughts?
TIA

The AC is under engine ECM control, so would normally maintain idle speed when the AC compressor kicks in.

The AC clutch draws about 5 Amps, nothing like 30, or it would burn out very quickly.

If there is condensate dripping out the drain tube, then it's a good sign the AC is working, as the evaporator is getting cold enough to condense the moisture out of the air.
If the heater control is pointed towards either of the two window settings, the AC works automatically, even if the AC switch is off.

Thanks, interesting info, I didn't know about the window setting and never noticed that, this is a FL1, are you sure that happens?
The key question is, why don't I noticed the extra load on the engine like I used to? I would always notice a significant performance lack with the AC turned on due the compressor load on the engine (had this with numerous older cars), why isn't it doing that anymore?

The key question is, why don't I noticed the extra load on the engine like I used to? I would always notice a significant performance lack with the AC turned on due the compressor load on the engine (had this with numerous older cars), why isn't it doing that anymore?

Click to expand...

afaik .. the ecu compensates for the ac compressor load ..
at least it does on mine [ 2006 manual td4 ] ..
e.g. on idle .. turn on the ac .. and the idle rpm raises slightly ..
`````````````````````````````````````````````````````````````````````````````````````````

on idle, I turn on AC, no change in RPM, nothing at all, it used to drop slightly and then recover to normal idle, not anymore.

Maybe there was too much oil in the AC system, prior to it being refilled?
Oil causes drag, which will pull the engine speed a bit. However as the ECM compensates for the AC load, any change in speed would be minor.

The AC definitely activates automatically, when the flow selection is at a windscreen setting.
Most cars do this, although some only on the screen only setting, like the wife's VW.

Air temp drop can still be used to test.
Also test air speed to check for blockages in pollen filter

When the ambient temp is 5c it's impossible to know if the aircon is cooling the air as it's already cold.
New pollen filter recently fitted.