My a/c condenser has a leak, it's been checked and it's not the compressor or the evaporator core. The system is empty no pressure in it. How hard is it to replace it, I was thinking of doing it myself (haven't looked into yet) as the garage wants £355, plus the condenser, plus the gas. All told over £700, I was thinking after replacing it I could get one of those kits from Amazon to recharge it. Has anyone replaced one and can give some tips, be much obliged or do you think it's a no go for diy?

Definitely not a DIY job, the system must first be vacuumed-out (usually for several hours or overnight) to remove any moisture after replacing the condenser and the drier - the vacuuming also confirms if the system will hold pressure or not - then the correct gas/lubricant charge has to be measured into the system.

All the above requires specialist equipment.

Not that hard to change, if you're competent enough to remove the bumper readily.

Home/DIY refilling is definitely a bad plan though.

14 hours ago, Warrior193 said:

....the system must first be vacuumed-out (usually for several hours or overnight) to remove any moisture after replacing the condenser and the drier - the vacuuming also confirms if the system will hold pressure or not - then the correct gas/lubricant charge has to be measured into the system.

All the above requires specialist equipment.

While the statement above is correct, I have DIYed it at home on the driveway, replacing condenser/dryer together with a failed AC compressor (in my Mk3 vRS, back in June 2023, no gas in the system).

However, you do need a decent vacuum pump and twin gauges as the system first needs to be emptied of air and more importantly moisture, otherwise water may freeze and cause blockage. You also need specialist oil and gas, the generic "airco top up" kits won't do.

The cost of refilling HVAC yourself at the time was under £150 including pump , pressure gauges and hoses/adapters (under £80 all in), synthetic oil useable with both R123a and R1234yf (either/or, not a mix) and the gas. At the time, half decent Chinese vacuum pumps and gauges kits were cheap, not sure now.

3 years on, vRS's AC works just fine with no topups since, so I must have done something right...

Getting hold of gas without any oil mixed into it was an issue, though after that job, for a HVAC topup on the other car, I have figured a way to filter out oil, sealant and dye from Halfords supplied gas/oil topup mix by running it through an inline oil/dye injector filled with folded, good quality paper towel

HTH

3 hours ago, dieselV6 said:

While the statement above is correct, I have DIYed it at home on the driveway, replacing condenser/dryer together with a failed AC compressor (in my Mk3 vRS, back in June 2023, no gas in the system).

However, you do need a decent vacuum pump and twin gauges as the system first needs to be emptied of air and more importantly moisture, otherwise water may freeze and cause blockage. You also need specialist oil and gas, the generic "airco top up" kits won't do.

The cost of refilling HVAC yourself at the time was under £150 including pump , pressure gauges and hoses/adapters (under £80 all in), synthetic oil useable with both R123a and R1234yf (either/or, not a mix) and the gas. At the time, half decent Chinese vacuum pumps and gauges kits were cheap, not sure now.

3 years on, vRS's AC works just fine with no topups since, so I must have done something right...

Getting hold of gas without any oil mixed into it was an issue, though after that job, for a HVAC topup on the other car, I have figured a way to filter out oil, sealant and dye from Halfords supplied gas/oil topup mix by running it through an inline oil/dye injector filled with folded, good quality paper towel

HTH

Thank you for that, very comprehensive answer, I may look at doing it through the winter ready for next summer. Not in a rush as the weather here has started to change, Autumn/Winter comes early up here. I may ask around meantime to see if any of the garages (limited choice) would be willing to recharge it after I've replaced the condenser. I see complete kits on Amazon inc pump for about £180. A question, why would you need gas without oil? Then get the oil separately. I figure even if it costs £300+ for DIY I will have saved over £400. Shouldn't be a problem removing and refitting the condenser, (I trained as a mechanic looong before a/c on cars).

The oil in "airco topup" kits is of unknown quality (unlikely to be synthetic/durable), usually contains dye and sealant. In large quantities, it clogs the system, expansion valve in particular, which really is a dog to clean. There is also way more oil in these kits than is needed for a full refill.

Much better/easier to measure the correct amount of synthetic airco oil, it will last a lifetime if no further leaks and protect the system from wear. I used Denso DND12250 or ND-oil 12. Expensive at over £20 per small can, but considering I also installed a brand new Denso compressor at the time, worth the extra peace of mind.

As an aside, for compressor replacement jobs (not this one), I think Denso ones are worth it despite much higher price , better compressing and much better overpressure valves than cheap Chinese substitutes. If there is even momentary overpressure or blockage, the valve on compressor will dump excess oil / gas but otherwise no damage / nothing to write home about. Compare this to once-only, cracking overpressure valves of lesser alternatives that basically require you to get a new valve (or a new compressor!) every time the pressure spikes. In DIY scenario, paying more for a decent compressor makes for lower long term expense.

Condenser / dryer is less critical, Denso ones are again good, but a tad pricey. I have used a Ridex condenser/ dryer from Autodoc at half the price of Denso, works same as OEM, though I had to file slightly one of its aluminium mounts to get it to fit properly. HTH.

3 minutes ago, dieselV6 said:

The oil in "airco topup" kits is of unknown quality (unlikely to be synthetic/durable), usually contains dye and sealant. In large quantities, it clogs the system, expansion valve in particular, which really is a dog to clean. There is also way more oil in these kits than is needed for a full refill.

Much better/easier to measure the correct amount of synthetic airco oil, it will last a lifetime if no further leaks and protect the system from wear. I used Denso DND12250 or ND-oil 12. Expensive at over £20 per small can, but considering I also installed a brand new Denso compressor at the time, worth the extra peace of mind.

As an aside, for compressor replacement jobs (not this one), I think Denso ones are worth it despite much higher price , better compressing and much better overpressure valves than cheap Chinese substitutes. If there is even momentary overpressure or blockage, the valve on compressor will dump excess oil / gas but otherwise no damage / nothing to write home about. Compare this to once-only, cracking overpressure valves of lesser alternatives that basically require you to get a new valve (or a new compressor!) every time the pressure spikes. In DIY scenario, paying more for a decent compressor makes for lower long term expense.

Condenser / dryer is less critical, Denso ones are again good, but a tad pricey. I have used a Ridex condenser/ dryer from Autodoc at half the price of Denso, works same as OEM, though I had to file slightly one of its aluminium mounts to get it to fit properly. HTH.

Thanks again, as the refrigerant cans are pressurised, how do you get the oil in separately?

You can use inline oil/dye injector can, basically an openable metal can plumbed inline or via a tee with gas. you fill the can with oil and then pump gas through it making sure oil goes with the gas. The nice thing about using this way is that you can also vacuum impurities from the new oil, just make sure the new oil stays in the can while you pump the system out. There exist also standalone oil injection kits (think high pressure syringe), but I'd steer clear of these as it is too easy to reintroduce air/moisture.

As I had said earlier, another oil/dye injector can filled with filtering paper in it can be used for opposite purpose, i.e. extracting oil from the gas.

One other thing I remembered about the job is that to get really good vacuum from the budget vacuum pump, you need fresh oil in the vacuum pump, in my case I emptied the system, closed off the pump, changed the vacuum pump oil again then ran it and then reopened the valve to the pump. I was able to get a lot better vacuum in that way, I think some of the remnant gases / vapours dissolve in vacuum pump oil and make for poor vacuum. Vacuum oil is not expensive, just mentioning it because it's worth getting a 1l bottle before the job.

Edited 32 minutes ago32 min by dieselV6