Just wondered if anyone else had experienced their AC performance dropping off over time, oddly it seems the hotter it is outside the worse the problem...

After about 30-45 minutes of driving the air is still cold, but the volume of air drops off, even though you can hear the blower motor still going.

If you turn the AC off for 10 minutes then the volume of air gradually increases - interestingly it also stays cold for a good 5 minutes, which is what makes me think it's blowing over a block of ice...

After 10 mins of defrosting, I can then turn the AC back on and the system performs normally again for another half hour.

Secondly, and possibly related is that if it is VERY hot outside, the AC seems very poor, by comparison to the 2002 L322 we have which will pump out ice cold air after a few seconds.

My thoughts are that the Evaporator temperature sensor could have failed and the system is using default values - does this make sense? I have queried the ATC ECU but there are no stored faults according to All Coms...

Dan 

Low gas pressure in the evaporator could will cause frosting as will a defective DXV valve. Low gas will also cause underperformance. Most systems will lose gas over a prolonged time which will eventually reach a point where the cycle ceases to work.

I take it you've had the pressures checked? Should only cost £40 for a regas so its a pretty easy quick first step.

Thanks - I've ordered an evaporator temp sensor as that's the easiest thing to test at the mo. I live in Cornwall - Air Conditioning is seen as the devils work. I have to drive over an hour into Devon before I can even come across the likes of a kwikfit - let alone an AC Specialist!

I did have the system re-gassed when I bought it, hopefully it's not leaked out again Although I would have thought poor cooling performance and icing up shouldn't go in the same sentence unless it is a sensor failure?

I'll report back when I have replaced the temp sensor later this week.

Dan

 

Ah, its about the pressures - I won't bore you with it. Anyway good luck, bit upset by your post as I'm about to start a 8 month job at Pendennis Shipyard in Falmouth, facilities that bad down there? Already not relishing the prospect of the drive every weekend in a 4.4L

Looking at your picture, it's a serious problem - it's causing the world to ice up.

Dan

Have you got any further with this issue? I have similar symptoms.
I was thinking evap sensor too, from RAVE it looks reasonably straight forward.

Cheers 2012 4.4TDV8 VSE
2004 TD6 132k miles- SOLD
1995 Land Rover Defender 110 Tithonus Ex Military
1995 Land Rover Discovery 3.9i V8 manual

I say straight forward. I was wrong. Looks a pig, stripping half the dash out. All to change a £25 part.

LHD version seems easier.

A know it all friend suggest I try to rule out a leak in the system. I bought a £2 UV torch from ebay and found a leak in the bottom left hand corner of the condenser.
I replaced with a £85 Chinese one from eBay, seemed to fit ok and once gassed I have a working cooling system. I hope that's cured it?

Click image to enlarge