Aircon woes

Wow everything has changed here.

Anyway I have a 2002 Freelander TD4 whose Air-con is not working.

As ever I went down the re-gas route that most people go at a local very cheap quick repair center. When completed the ten year old that did it, (or looked that old), said after testing that it's not a gas problem but either the Air-con clutch or wiring for it are faulty.

Now I have to admit that I'm not an Air-con expert and have had little experience with fixing Air-con ut I've never heard of a clutch for it so I've checked on Google and there are such parts.

When the Air-con button is operated on the dashboard the engine noise level drops indicating extra load so to me it seems that the clutch must be engaging. Am I correct in my assumption or is there more to it?

In the meantime I'm going to do some light reading of my service manual in the throne room and see if I can't follow it through.

Any help would be most appreciated at this point.

Thanks in anticipation.
mediaseller

The "clutch" is part of the AC compressor.

If you switch off the AC and look at the pulley on the compressor, you should notice that the outside of the pulley is spinning but the bit sticking out of the middle of the pulley is stationary.
Switch the ac on at that point and you should be able to see that the bit sticking out starts to spin on a duty cycle (IE 30 seconds on, 30 seconds off) and will clunk as it engages and disengages. If this is happening then your system is electrically working fine.

Aaaaaalso... if your clutch *is* engaging, it means that you've got good gas pressure and something else has gone wrong.
If the compressor is running, the evaporator inside the heater is getting cold, it's the only thing that can happen.

The next question is when it was regassed, did they actually run the AC? Iirc the AC must be running while charging to get a full charge into the system, moreso when they're using a cheap charge mechanism.

Btw, the AC on the freelander isn't really anything to write home about, it won't blast icy cold snow at you, it sort of gently wafts a cool breeze.

Ok thanks.

Having consulted the manual I have been out and looked in the fuse box in the engine bay and found F9, (10A), pulled out and laid in the fuse tray. When I put it back in and tried the Air-con it now blows cold air but there is a terrific din coming out of the engine bay like a hammer drill.

It sounds to me that either the relay is chattering or the clutch itself is faulty and may be engaging, disengaging at a rapid rate.

Do you guys know what it could be or if it's a difficult/expensive fix?

Thanks
mediaseller

Ugh.
That's one of either two things - either the clutch has died (how many miles does the car have?)
Or they've put so little gas in it that it's getting in a horrid feedback loop - gas pressure on low side good -> compressor kicks in -> gas pressure on low side drops -> compressor kicks out -> gas pressure on low side good... and so forth in a rapid fire on off.

The only way to check is to see what the low pressure sensor is doing.

Well I've been back out again and swapped the horn and Air-con relay and it's still like a hammer drill so I know it's not the relay.

When I switch the Air-con on there's a really strong smell of what I think might be refrigerant gas and I wonder if this is because it's not worked for a while?

Thanks again in anticipation.

B34R said:

Ugh.
That's one of either two things - either the clutch has died (how many miles does the car have?)
Or they've put so little gas in it that it's getting in a horrid feedback loop - gas pressure on low side good -> compressor kicks in -> gas pressure on low side drops -> compressor kicks out -> gas pressure on low side good... and so forth in a rapid fire on off.

The only way to check is to see what the low pressure sensor is doing.

Click to expand...

I'm not sure about the low gas level though I can see your point about the feedback loop. My reasoning is that the fuse was originally pulled so the last owner must have had the same problem. Could I bypass the relay for a quick check of the pressure feedback loop?

clutch itself is faulty and may be engaging, disengaging at a rapid rate.

Click to expand...

had similar happen to me when i d.i.y. re-charged the AC ( halfords kit )
the kit gauge was faulty ( had used it twice ) and leaking ..
so ended up overcharging the system ( i.e. over pressurised )

the AC clutch would engage and disengage rapidly ..
i did drive down a fairly steep hill in 3rd gear ..
and the rapid AC clutch action felt as if the brakes were being applied on-off ..

anyhow .. drove it home .. and with the AC 'on' .. gradually let pressure out of the system
untill the clutch stayed engaged all the time ..

AC now working fine .. wasn't as cold as i would have liked beforehand ..
( that were during this summers brief heatwave )

Yeah, sorry I forgot that the pressure switches also have a high pressure cut out too.
You can tell what's going on by checking to see whether any of the pressure switches are flipping state.

If you can /smell/ gas there may be a pressure blow off happening somewhere which would indicate overpressure?

Hi HD3.

I tried your method and it worked. Well 95% of the time because when I go down steep hills or turn hard left or right the noise comes back but not as loudly. I do feel rather chilly now which is good.

Perhaps it is blowing off surplus gas and may settle down on it's own.

Cheers
mediaseller

and may settle down on it's own.

Click to expand...

i'd be wary of leaving it to settle on it's own ..
if it's cutting in and out .. due to too much pressure ..
surely it would stress the system ??

don't know where it would blow off surplus gas ..
( i.e. discounting a blown seal .. or leakage elsewhere )
am not aware of any device in the system to intentionally do that ..

if it cuts out cause the pressure is too high .. must be a safety cut-out to hopefully prevent it blowing a seal
or over stressing the compressor itself ..

don't know why turning hard would cause it ..
( then again .. i sure aint no AC expert
steep hills with engine braking higher rpm .. could figure that the compressor is turning faster
compressing the gas faster .. raising the pressure faster ..


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

when i did mine .. i let the engine idle .. AC on full-cold .. fan on '4' ..
and made sure it idled .. maybe 3 to 5 .. minutes without the compressor cutting in and out
( and making that nasty noise ) ..

maybe you need just a tad more to de-pressure it .. .. just a tad ..

Hi.
Just an update. It's been running for nearly a week now without any issues just driving along in a straight line, however as I said before the fault returns when I steer hard left/right or reverse. It's just wierd.
I don't know if it's that when extra load is put on the engine, (steering or reversing), it sets up a sympathetic frequency causing what we call in the controls industry a feedback loop causing the clutch to engage and disengage rapidly on the compressor.

Just before you ask I have not yet had the gas pressure tested again yet. You would think that if it were gas pressure then it would happen all the time.

Thanks again
mediaseller