AC Condenser Replacement Procedure

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This topic contains 6 replies, has 4 voices, and was last updated by Jason Lei Jason Lei 7 years, 10 months ago.

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  • #632285
    Jason Lei
    Jason Lei

    Friend has a car that got into a light front end collision (no clue how).

    AC condenser is curved
    Radiator is curved
    Radiator/AC condenser bracket is curved

    No sharp bends or cracks I can visually see, as well as radiator still holds fluid (so no leak there).

    I will be replacing the radiator, bracket, and AC condenser and wanted a proper procedure dealing with the AC system.

    My main concern is the AC condenser (watched ETCG’s AC videos, but wanted clarification).

    In the most efficient way what series of steps should I take?

    -Purchase manifold gauge to test pressure to see if it needs to be evacuated?
    -Dye test it? (if its cheaper and just as effective as above)
    -If it needs to be evacuated, what type of machine does a shop use? and roughly how much do they charge

    -If I have to get it evacuated do I need to do anything besides evacuate it; or do I leave it at atmospheric pressure to do the replacement?

    -Replace the AC condenser – cap ends while I replace, oil to lube, and reassemble

    -After the replacement I would need to put it under vacuum, then fill with R134a correct?

    Ultimately, I know I can replace an AC condenser myself – dealing with purchasing gauges/vacuum pumps etc, is it easier to take it to a shop to evac; take it home make a AC condenser replacement, and bring it back for a recharge?

    Any step by step a shop/DIYer would take would be great information before I actually start.


Viewing 6 replies - 1 through 6 (of 6 total)
  • Author
  • #632371
    Lorrin Barth
    Lorrin Barth

    First of all lets talk about refrigerant. Get the liquid on your hands and it will burn you. Get liquid refrigerant in your eye and it will blind you.

    Second, all you need to do is depress a schrader valve to see if anything comes out to know if it needs evacuation. See the above warning.

    Replacing the condenser is simply unbolting. Lubricate NEW o-rings with compressor oil and observe the tightening torques when replacing. Then take it to the shop for leak testing and refilling. Be sure to tell them the condenser was replaced so that they can add the appropriate amount of oil.

    Jason Lei
    Jason Lei

    I can depress either or schrader valve correct? Or specifically low side or high side?

    Am I to expect the liquid to come out under pressure (i.e. shooting out) or just accumulate as a pool of fluid?

    Is there a specific oil, or any compressor oil would be okay to lubricate the new o-rings?

    Lorrin Barth
    Lorrin Barth

    [quote=”misturjason” post=117997]I can depress either or schrader valve correct? Or specifically low side or high side?

    Am I to expect the liquid to come out under pressure (i.e. shooting out) or just accumulate as a pool of fluid?

    Is there a specific oil, or any compressor oil would be okay to lubricate the new o-rings?[/quote]

    Refrigerant and compressor oil will spray out if any refrigerant remains. You won’t see any pools of refrigerant, it evaporates very quickly. That is what makes it dangerous. The fast evaporation freezes any skin it touches.

    It is kinda like working under a car with a torch. There’s a lot of bad things that can happen here too. However, people do it all of the time. You just have to understand the danger and take precautions. Goggles and gloves would be a good idea when working with refrigerant.

    Which schrader valve – it doesn’t matter.

    For the o-rings use the same oil that goes into the compressor. I’d suggest taking a tiny jar to the shop that will be recharging the system. If they want your business they will give you some.

    James O'Hara
    James O’Hara

    First off because I have EPA 608 and 609 licenses i have to say venting of refrigerant is illegal. This is because it eats our ozone. Now with that out of the way i would suggest low pressure side. If you are going to see if anything comes out. Wear all leather gloves without holes if you do this refrigerant on the hands does not feel good (been there done that putting a schrader back in as a new tech stood there freaking out). It is also corrosive to plastics. Most vehicles are built with refrigerant with dies in it. Depending on when/how you lost your a/c will depend on whether weather has washed away he dye or dirt has covered it up. Easiest way to check is use a blacklight lightbulb in a old school drop light. If you have yellow tinted glasses that are not polarized use them. You are looking for a glow like that of a glow stick it is normally green or blue or pink. This will let you know where your leaks are because you may have more then just the condenser. The machines they use at service garages are normally about $1k and robin air is the best but, not something for the diy. You can get away with a manifold gauges, vacuum pump, black light bulb in a droplight housing, mineral oil, measured refrigerant bottles and schrader valve tool. Also a recovery canister once again because venting refrigerant is illegal.

    I would first check to make sure that any sensors coming off the a/c system were not broken and/or the wires cut. If so fix this first as this may solve your problems. Also check the compressor wires they are for your clutch. If you have a ohm meter ohm the wires coming out the compressor make sure they ohm relatively low like max of 15 ohms. If any of the above is bad that is what must be repaired first.

    Now if you have anything in the system take it to an automotive shop and have them evacuate/vacuum it down to 0psi not lower if you can help it or you can vacumn it down into a cannister. Have them write down the amount of oil pulle dout during this process. At 0psi it is relatively neutral to the outside air and will not suck contaminants into the system when you open it. When you go to replace the condenser if mounts are bent/broken it is going to be a pain just a heads up. Anytime you open an a/c system it is recommended you replace the receiver/dryer or accumulator. Also always use new o-rings and d-rings if it has d-rings. Lube your o-rings and d-rings with mineral oil. Do not use the same oil as you would for the system it will attract moisture causing the o/d rings to decompose or the metal to oxidize and force open the connection and cause a leak. Do not use the mineral oil in the actual system if it does not call for it. The label under the hood should let you know how much refrigerant/type of refrigerant and what kind of oil to use in the system. There is also normally a spec for how much oil to add per piece removed off the vehicle. To add oil remove a schrader once the system has reached 0psi and dump in the specified amount per component(s) removed. Schrader valves are easily broken so be careful especially when reinstalling. I would suggest a new schrader valve if possible. If this is going to take you more then a few hours put a ziploc bag over any openings in the system and tape it shut against the line moisture is very bad in an a/c system. Last before you refill with refrigerant vacuum down the system for at least 45mins to 1 hr 15 mins. If it has been open for a day or more I would say 2hrs min. This helps to evaporate and pull all moisture out of the system the down side is it also pulls out oil which then has to be re added however much came out. Pulling a vacumn on the oppisite side that you added oil is recommended. when you pull down vacuum if the gauges don’t read to zero within 30 secs of each other you more then likely have a restriction which is either moisture in the system or contaminants from your reciever/dryer or accumulator desiccant bag breaking or dirt in the system or your compressor failing. If that is the case your hvac system has to be completely torn apart flushed to clean the foreign material out. Then dried with dry nitrogen reassembled with a new reciever/dryer or accumulator. If the compressor failed a new compressor, and new high and/or low pressure switches. Aka a/c shop or you are looking at 2-3 days full of work and about 1 week worth of looking around to find where you can get dry nitrogen and the valving to hook to the system and regulate it down so you don’t blow your a/c system apart. If you replace the compressor you must drain the oil out of it and add new oil to it of the measured amount removed from the old compressor + removed from the system so long as it does not exceed max system oil requirements.

    If I were you I would check for leaks with the black light bulb and the glasses if you have them. Take it to an a/c shop or a shop with a good a/c reputation. Have them evacuate down the system to 0psi. Fix all the things you saw wrong. Take it back to them tell them to vacuum down the system per the times listed above. Perform a leak test. If it passes recharge the system and add the oil needed for xyz components removed. That way all you are doing is replacing bad parts and o/d-rings. If it doesn’t pass the leak test you have 2 options recheck for uv dye or have them recharge it and add uv dye then look for the leak. Once it passes the leak test as long as the electronics are good, there are no contaminants, and neither the compressor and/or receiver/dryer or accumulator has not failed your system should work beautifully. This will cut a large majority of tools and expenses out of the equation for you. Also it is unlikely that the components I listed will have failed but, not unheard of.

    That is the proper way of doing things to get a system that doesn’t cause you issues later on. Some a/c shops will skip steps i listed etc but, if you want it to work properly that is what you have to do. HVAC can be a pain in the but and it is expensive as hell if you don’t do it yourself and now you know why. This is advice and to be used as such. Proper research is up to you and I am not liable for any damages.


    A person can get themselves into real trouble when fooling around with an A/C system if they know nothing about the subject no matter if it’s discharging refrigerant or during the charging process.

    As mentioned, frostbite and permanent blindness is a real possibility. I’ve seen a few refrigerant explosions with guys in the shop who were very proficient in the A/C field.
    A second of carelessness and that’s all it took. In both of their cases they were just lucky not to have suffered injuries.

    Jason Lei
    Jason Lei

    Thank you guys for your replies. It’s all very informative, however, I just want to be most efficient before taking it in to a shop. I definitely will have a shop evacuate the system if there is any refrigerant left.

    My main concern is ensuring that there is, or there isn’t any refrigerant left in the system. Aside from depressing the schrader valve, I would love to check with a DYE test, is there a proper procedure to induce DYE into the system?

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