Thread: D4 A/C Compressor issue

Definately get a condenser, especially if your not equipped correctly to flush at home. Get them to jam at least 100ml of extra oil in it.

Buy genuine O rings for everything

Originally Posted by josh.huber

Definately get a condenser, especially if your not equipped correctly to flush at home. Get them to jam at least 100ml of extra oil in it.

Buy genuine O rings for everything

Sounds logical, but what is the rationale for the extra oil please?

The compressor pictured has a clutch which is powered on when you turn on the a/c. The variable control valve varies the capacity of the compressor to keep the correct flow of refrigerant required. The clutch does not cycle on and off as in older thermostatically controlled systems.
If you don't understand how the system works why would you try and fix it yourself.
The first thing to determine is WHY did the compressor fail, or is it just a failed valve. If a complete compressor failure then a new TX valve and drier and condenser is called for.
If the system was low on refrigerant, where did it go. Modern systems do not leak from compressor seals or hoses as did older ones. Did the system suddenly stop cooling, or was it not performing properly for some time.
These are all questions that need to be answered before spending big bucks on parts that may or may not be the cause of the failure.
Consult an expert.
LuckyLes

Originally Posted by gavinwibrow

Sounds logical, but what is the rationale for the extra oil please?

Oil coats the inside of all parts. So by changing the condenser, your removing about 40ml of oil, the drier about the same, the compressor will come short too.

I can't remember the number, but I "THINK" the compressor came with 70ml and the system is 240ml.

The quantities are in an old post of mine, but I always add oil, a bit extra is allot better than not enough. To much oil decreases cooling efficiency, not enough kills compressors. I've never noticed a cooling deficiency per say, but the theory is solid.

Why not pour the oil out of the old compressor and measure it?
That will give an accurate measurement of oil the new compressor will need.

Same for condenser and drier,but maybe more difficult,possibly have to leave them draining over night.

The evaporator will also have oil in it,and in some cases can by oil logged,particularly when the system has been operating at low pressures,such as when low on refrigerant,but a huge job to get it out and drain.

Originally Posted by scarry

Why not pour the oil out of the old compressor and measure it?
That will give an accurate measurement of oil the new compressor will need.

Same for condenser and drier,but maybe more difficult,possibly have to leave them draining over night.

The evaporator will also have oil in it,and in some cases can by oil logged,particularly when the system has been operating at low pressures,such as when low on refrigerant,but a huge job to get it out and drain.

As for draining the compressor, yes 100%. That's how I worked out they needed so much more oil.. You'll never drain a condenser or hose as it's coated the inside. There are charts for how much oil to add per metre of hose etc.

I normally drain the compressor and change the oil to a synthetic oil as it's non hygroscopic then flush the system. Add the appropriate amounts where I can.

Originally Posted by josh.huber

The ones without a clutch will literally just die and take the belt with them.. Same as a dead water pump etc

the clutchless ones have a sacrificial pulley to pump connection so in theory if it seizes that gives way and the belt can keep going.

I was able to cancel my order and am getting a condenser on everyones recommendation and also for that fact that i have to pull the old one out to get to the dryer

Mine had not leaked, gas ok, for some time would take 10mins to produce cold air, and then sometimes 30 mins, and now not at all. Only making hot air if running, so the pump must by circulating and getting power.

It could be valve inside pump, but not sure if even replaceable on internal controlled, consensus from my other posts in threads seems to be safer to just replace pump for the confined work involved which is the biggest issue.

LR gives these recommendations re oil and gas, apart from the gas capacity, the oil recommendations are the same for the 2.7D and V8 petrols in my manual.

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Plot twist, (i should have looked at the one on the car sooner) thats not the compressor I have/need (currently cancelling order, again...)

LR020449 (sanden) with clutch is in l322 (same engine), and for my l320 (and this is confirmed by lr centre uk, and my eyes) that i need LR018405 (denso) (which is nearly twice the price)

And as it turns out is an externally controlled displacement pump with no clutch, so im back at square one.

And it turns out mine has green oil over it so it so must be leaking, I can only hope the natrad tech was right that its gas level was ok, and its not actually empty and slowly destroying itself and the rest of the system.

I believe this is the one

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DENSO 7SEU17C dcp14019