So I brought my 2007 G35x Sedan into the shop because of my A/C not working, and when I measured the refrigerant levels I got a firm 0 on both the low and high pressure sides, so indicating a leak. The shop got back to me today and told me that the refrigerant is leaking from the compressor. I asked them what my options are for that, and they told me they have never had luck rebuilding a compressor after something like this happens, and want to charge me $1400 to replace the A/C system. They also told me that if I replace the compressor, Im better off doing the expansion as well, and other components of the A/C. I am a DIYer myself, so now im questioning everything. I can say I am not ready to drop $1400 on the compressor replacement when I know I can get a compressor for 200-400 online, new. My question is, how likely is it that refrigerant is really leaking from my compressor, and if so, do I even need a new compressor, or is that something where I could possibly replace an O-ring or rubber seal? Is any of this work I can do myself on jack stands? Ive done belt tensioners, and alternators, so worked right up in that area next to the A/C compressor. What's my best bet from here out? should I start by taking the thing apart, and seeing if I can identify any issues with it?

 

They don't want to rebuild the compressor because they don't know what other possible damage might be lurking inside and having a pissed off customer coming back a month later paying ANOTHER round of shop labor fees to do the job again.

That's why they want to just use a new unit.

I've replaced the front shaft seal on literally dozens of compressors over the years (it's always the front shaft seal that goes out, the one behind the magnetic clutch/pulley assembly. Usually they require a specialty puller to get them out but it's a very straightforward repair and the seal is usually $15 or so. The shaft from the pulley rotates on that seal and it just wears out over time. Use a puller and remove the magnet clutch, another puller to remove the pulley, then it's usually just a C-clamp that holds the shaft seal in place. You could technically not use a specialty puller for the shaft seal, they've not pressed in very hard and you can use two dental picks, rip through the rubber and hook under the metal on two sides then just pull it out. Or use a small collet puller, the trick to using a shaft seal puller or collet puller is to just BARELY snug them up to grab the lip on the shaft seal. If you tighten it any more than that you're just wedging it up against the compressor housing and it won't pull out. Less is definitely more.

Yes you typically want to replace the expansion valve/orifice every time you put in a new compressor, same with the drier.

If you're mechanically inclined you can do almost all this work yourself btw, the system has already purged so no worries about dumping the AC into the air, the car already did that part for you. The expansion valve/orifice is held on by just a couple bolts, there are o-rings that need to be lubricated before you reinstall. The drier is simple also, just a couple metal refrigerant lines and a bolt to hold it down. Use PAG 46 oil to lubricate those o-rings.

Then buy a cheapo R134A manifold to pressure test the system yourself, you'll need an air compressor as well (ANY compressor that can do at least 100psi is fine, even tiny ones) and make sure to drain any extra water from it and preferrably install an in-line water trap so you aren't putting any extra moisture into the AC system. Hook to the high and low pressure sides, hook the AC compressor to the middle port on the manifold (suction line), crank the compressor up to 100-150psi (don't exceed 200psi if you have a massive compressor), then open the high and low valves on the manifold to charge that pressure into the system. Close off the suction line then just simply wait and watch the gauges. I like to leave them hooked up at LEAST 1 hour, preferably 24 hours. Take a picture of the gauges with your phone, also write down what the temperature was when you took that picture. Come back the next day or later that evening when it's the same temp outside again and those gauges should still be right where they were.

Either buy refrigerant leak bubble solution/leak detector or make some soapy solution yourself, put it in a spray bottle, spray down all the fittings (including the manifold itself), if there's a leak it will start making big bubbles for a large leak, white foam for a small leak.

Heck if you want to go even further you can buy a cheapo AC vacuum pump on Amazon, pump the system down, cheapo oil injector, 6 ounces of PAG46 oil for the oil injector, and 1.2 LBS of R134a and just charge it yourself, it's really not difficult at all and only costs about $75 for a vacuum pump, $30 for an oil injector, $50 for a R134a manifold and hoses, couple extra brass fittings from Home Depot to connect your air compressor and oil injector to the suction line of the manifold, then all you need are cans of R134a and another adaptor hose to hook them to the suction line.

Or you can get it all to that point just prior to adding refrigeration (you could skip the vacuum draw down as well), and let the AC shop refill the system once you have done the work.

It's definitely not rocket science, it's mostly just viton o-rings and a couple bolts and they charge MASSIVE amounts of money to repair it because most folks don't know better.

 

It's literally twice as difficult to do a timing chain on these cars compared to repairing AC stuff.

 

learned something today! Also - timing this weekend, so that makes me feel better … especially after watching the cloyes video.

 

For me it's the concern that I didn't get all the debris out of the system and I'm risking all this time and money with an uncertain outcome if I don't change literally every part including pressure lines etc. I think if it were that easy to do and do properly, more people would DIY these. The fact that most people don't just leads me to believe that too many regular DIYers tried it with bad outcomes. I see more people talk about taking their CVTs apart and repairing them than talk about repairing their AC systems.

 

The only time you need to worry about debris in the system is if you actually kaboom the compressor and it shats metal dust into the system, at that point you replace everything including the heater core.

You can get a REALLY good idea of what the inside looks like just by removing the orifice/expansion valve. Swab out the line and around the orifice with a clean q-tip and see if there's metal glitter up inside the line set. If it's not glittery you're fine.

Even if you get a little moisture in the system from your air compressor it's not too big of an issue, when you do the vacuum drawdown that is removing the moisture from the system. Just read reviews to make sure the vacuum pump can handle 29-30 in/hg (this is also normally the lowest value on a set of R134a manifold gauges). I use this one from Amazon for R134a stuff. Also note that a lot of people complaining that their vacuum pump won't pull 30 inches PROBABLY have a small leak in the system still...

Let the vacuum run for 1-2 minutes if you know the system didn't get moisture into it (like if you used nitrogen to do the pressure test), run it for 8-10 minutes if you used an air compressor just to be sure it's fully evacuated.

 

Cleric is one hundred percent right. I was also quoted around 1200 to fix my ac, bought the compressor and ac kit of amazon for less then 500 and did the install myself. Did the vacuum and leak test myself with the kit. Also the refrigerant is cheapest at walmart.

 

Yeah that kit looks pretty complete, you would still need an oil injector though.

 

Also, if you're using a NEW compressor you would add the factory specified 6 oz of PAG 46 oil to the system, if the system leaks out and you are just replacing an o-ring or seal or something you only add 2 oz of oil.

Typically with a slow leak you only lose 1.5-2 oz of oil from the system, sometimes a big catastrophic leak will blow out a little over 2 oz but that's it.

You always lose oil with an AC leak though, just use your best guess how much oil to add. If you lose the system charge a month later I would only add an additional 1 oz. You don't want too much oil in the system because it does take up volume which means less refrigerant.

This is the big issue with those AC Pro do-it-yourself bottles, they have a lot of extra oil in them and you can quickly end up with double the oil in the system and not enough volume for refrigerant.

 

While under extended Infiniti warranty back in 2013 or so I had mine let go.

AC clutch apparently seized and broke off pulley (it was sitting on underbody cover) and system opened up. I could hear the vacuum get released as I was accelerating on on-ramp to work.

 

Yeah it's pretty violent when the system quickly purges. One time I slipped on oil in the shop and caught myself by the AC line on a car with the bumper and grill removed, ripped open a fitting. GIANT CLOUD OF REFRIGERANT....

Sounded almost exactly the same as when you disconnect an air compressor hose.

 

Hi, I am thinking I am in the market to attempt this job as my AC system just catastrophically failed. I had just replaced the AC compressor belt and the system was working fine for a few days. Then on a cold start an instant decompression of the system and oil was sprayed everywhere. Question is, what causes this kind of total failure and do I just need to replace the seal, drier and valve or?

I also posted about it here.
https://g35driver.com/forums/g35-sed...happening.html

EDIT:
Ok after pondering on this I think I caused the failure by putting too much tension of the AC belt when I installed the new one. Question is did I just fry the bearings in the compressor by doing so? Am I looking at total compressor replacement or can I get away with just replacing the seals. #dammit.

 

i'd get a new one. ebay has OEM ones for about $250. here's the one i got when mine took a similar dump earlier this year: AC Compressor OEM DCS17EC fits Infiniti G35, G37, M35 QR | eBay

replace the dryer and all the seals (rockauto sells those). fairly straightforward job. dryer could be a biatch to get to, but not terrible. check your a/c lines with a flashlight to make sure they're clean (you'll hear a lot of online chatter about "black death", but don't get too worried yet).

 

It ended up being a burst high pressure hose.

Just in case anyone else has to do this. I discovered you can replace the drier without removing the radiator, fans and condenser. Just remove the front grill (very easy) and the left 10m bolt holding the radiator to the frame. This gives you enough wiggle room to hit the 10m bolt holding the drier on the condenser from the bottom and boom it comes right off. Takes the drier job from 2h to about 20min.