P38 air con

Just had air con re gassed by kwikfit. No leaks system full of gas but wont get cold. They told me it could be the air con compressor , is this an expensive fix , I'm in Bristol

Check the AC clutch is engaging.

Paul vice said:

Just had air con re gassed by kwikfit. No leaks system full of gas but wont get cold. They told me it could be the air con compressor , is this an expensive fix , I'm in Bristol

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I suppose the belt is in place?
You need to check the clutch on the compressor is operating, with the engine running, you can see the pulley turning and when the clutch engages the centre section should also turn.
On early cars, the clutch is driven directly from the HEVAC, on later cars there is a relay. Look at RAVE for fuse and relay. There is also the tristate switch etc to check. It's all in RAVE.
The compressors are pretty reliable.

Datatek said:

I suppose the belt is in place?
You need to check the clutch on the compressor is operating, with the engine running, you can see the pulley turning and when the clutch engages the centre section should also turn.
On early cars, the clutch is driven directly from the HEVAC, on later cars there is a relay. Look at RAVE for fuse and relay. There is also the tristate switch etc to check. It's all in RAVE.
The compressors are pretty reliable.

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Thanks for that Datatech but to be brutally honest I haven't a clue what I'm looking at I'm just wondering how much it will cost to get someone to fix it for me without paying land rover dealership prices

Paul vice said:

Thanks for that Datatech but to be brutally honest I haven't a clue what I'm looking at I'm just wondering how much it will cost to get someone to fix it for me without paying land rover dealership prices

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Diesel or petrol?

On the compressor you will see an electrical plug with two wires. Unplug this, start the car and set temperature to Lo. Now go back and reconnect the plug listen for a fairly loud click. If you hear that it means the clutch has engaged. If there is no cold air when the compressor is running you are probably low on gas. If it does not engage you could be very low on gas or there could be an electrical problem. Any garage can tell you if you are low on gas by checking pressures. I think this should be around 60psi after the system has settled down. For electrical you will need an LR specialist or become one by reading all the forums.

How did they refill with compressor not working is the question.

I think they might have noticed ?
Didnt realise that was how to check clutch ty

Had that.
When the compressor clutch frigged nice and cold. The sensor (threeway or trisate) was the problem as mentioned before.
You can test it, look at wiring diagram.
J

Just a thought, is the AC switched on? Kind of counter intuitive on the p38

Paul - even if you consider yourself an amateur, don't hand the car over to a mechanic until you've a better idea of the issue IMHO "It must be the compressor" is the first refuge of the "haven't got a clue" tyre-fitter, and has been used on me more than once.
1. Do you have the fill cert from Kwik fit - how much refrigerant did they remove, and how much did they replace? and the same for the oil...
2. Belt (must be there !!)
3. AC clutch - take the car on a short run, park it up, lift the bonnet and hit Lo with AC on (ac button and light off). You should be able to see (and hear) the ac pulley lock up, and the a/c clutch plate spin. If it doesn't get a spanner (ferrous) and put it near the clutch plate (Warning - these are moving parts, but i assume you are an adult) . If the plate is magnetic then you have power to the clutch (hooray). Whack the clutch plate with the spanner, and it will probably lock on, and cabin will get cold.... this means you need to play with the clutch gap. Use filter paper to clean any crap from between the plates, and if that doesn't work you will need to remove the clutch plate and see if you have a shim you can remove. If the clutch didn't magnetise, then you need to check for 12v and earth at the incoming circular plug on the compressor - if the voltage is not there, or was too low then you need to trace further back through the electrical and control circuit.
4. check fuses/ relays
5. using some extension wires apply 12v and earth to the compressor (i took them off a relay in the fuse box) - does the clutch engage (if so then your compressor, or at least the clutch is most likely fine)?
6. Get a UV light in the engine bay after dark and see if you can see any ( green) leaks especially around the condenser or the lines.

To get 12v at the compressor there is a sequence of events that must hold true - cd be different for a diesel, but for a V8, HEVAC requests AC (Lo on the controller), ECM grants the request, pressure is not too high or too low (pressure switches) etc. If you have a nanocom you can intercept the AC request and grant, to try and identify the "blockage". The trinary switch is probably a bumper-off job, but can be done without refilling the system, not a terribly hard job though.

At least if you pass it to a mechanic at this point you have eliminated the easy fixes and are better armed not to take their BS. But hopefully you are half-pregnant at this point and see it through to the end with the help of the forum : o)

Your info page say`s you have a diesel so the compressor will be bottom left hand side of the engine you can get to it from underneath the car.

Paul vice said:

Just had air con re gassed by kwikfit. No leaks system full of gas but wont get cold. They told me it could be the air con compressor , is this an expensive fix , I'm in Bristol

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You won't have paid anything then i take it?

brianp38dse said:

Your info page say`s you have a diesel so the compressor will be bottom left hand side of the engine you can get to it from underneath the car.

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Only if you remove the undertray

I wonder if there is really any gas in there?

Datatek said:

I wonder if there is really any gas in there?

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The automatic regas machines must use different methods than the standard manual regas procedure. Normally you would vac down the close the LP and HP valves, bleed gas to fill line then start engine and set aircon to full low temp and open LP valve. As gas is ingested compressor should start up and distribute gas around system LP valve is then closed when normal green line gauge pressure is obtained. Job done. Being able to fill with gas when the system is not actually working is a little stupid in my view.

I would assume Kwik-Fit removed the gas when they failed to get it working ?? In which case the A/C clutch will not engage normally no matter what. Only way to test it will be to either apply 12V directly, or bypass the 3-way switch.

pwood999 said:

I would assume Kwik-Fit removed the gas when they failed to get it working ?? In which case the A/C clutch will not engage normally no matter what. Only way to test it will be to either apply 12V directly, or bypass the 3-way switch.

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If there is no gas in the system. Checking the clutch engages with engine off is fine, but it's not a good idea to engage it with engine running.

wammers said:

The automatic regas machines must use different methods than the standard manual regas procedure. Normally you would vac down the close the LP and HP valves, bleed gas to fill line then start engine and set aircon to full low temp and open LP valve. As gas is ingested compressor should start up and distribute gas around system LP valve is then closed when normal green line gauge pressure is obtained. Job done. Being able to fill with gas when the system is not actually working is a little stupid in my view.

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yeh - mine got automatically filled without needing to run the compressor, fully evacuated, then pressure tested, then filled. It's not until the end that you then turn it on and see if it works. No work, no pay (National) - silly business model !!

romanrob said:

yeh - mine got automatically filled without needing to run the compressor, fully evacuated, then pressure tested, then filled. It's not until the end that you then turn it on and see if it works. No work, no pay (National) - silly business model !!

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Mine was also vacced, leak tested and filled without the compressor running and I have also filled one with a DIY kit that did not require the compressor to run. Indeed the compressor will not run until there is enough pressure in the system.