I will go back to the shop and make the video with the gauges tomorrow, but as I remember from when I was there Wednesday , it was running at 150psi on both the high and low sides when it wasn't working, and then it was running at 40-50 on the low side or so and about a 175-180 on the high side when it was functioning

 

Do I need a cable to hook up to the OBD2 do this?..... By the way, I'm on about an hour commute during this conversation, and after stopping to vent a little more refrigerant off, it has started working again, but at the same time the overcast has returned even though the temperature is still around the same.

 

No the self-diagnostic doesn't require any tools, there's sort of a "pedal dance" to get the system into diagnostic mode then it displays on the screen all the various components of the AC system and it does a self test of them individually as you scroll through them. If there are any issues found it will display a trouble code for those individual items.

Check section ATC - Automatic Air Conditioner in the FSM.

https://www.nicoclub.com/infiniti-service-manuals

 

I don't see a section labeled ATC in the 2008 Manual. I only see HA - Heater & Air Conditioning System and HAC- Heater & Air Conditioning Control System...not finding "pedal dance" type instructions to get into Self Diagnostic

 

HAC, starts on page 44, Diagnose System.

 

When the system fails, is it always at a stop? Is your cooling fan working?

 

OK, so here's the latest. I know that I had a leak at the condenser that I've recently noticed and I just replaced it about a year ago so the company that sent it to me sent me a replacement and this weekend I set out to swap it out as well as evacuate the system and try to recharge it.

The very 1st thing that I noticed is in one of the pictures that you'll see here that the low pressure line coming out of the expansion valve had blown out, I just recently had the expansion valve replaced and thought it was just because he may not have latched it in good, but....

That logic may have changed after what happened today. I changed the condenser closed everything backup and pulled vacuum on the system and then lock the vacuum in for 30 minutes and everything held.

I added one can of refrigerant and the system began to cool, I didn't get pictures of gauges when it was working but the I want to say that high side was somewhere around 180 to 200 and the low side was between 45 and 55. Cooling was working.

Ar this time, I attempted to add more refrigerant and, The system stopped cooling and started to get hot, and the pressure started to build on the low side as you can see in the video, and then the pressure basically separated the connection by the low side access port, which is the same pipe that was blown off of the firewall at the expansion valve when I 1st started the job.

It seems as if there's something that is building pressure on the low side that at times can exceed the pressure on the high side weirdly enough... I thought I was really close to solving this problem today and then it just got way more complicated.

 

Cooling fan working?

 

Here's the video of the low pressure line popping off.


https://www.dropbox.com/sh/dj0kna2o3...38Yvsx1Ba?dl=0

 

Yes. The fans appear to be working.

 

If the fans are working you have a blockage, it’s most likely the expansion valve, that’s where I would start.
The lines should never blow off though, the compressor blowoff valve should actuate before that happens

 

Just had the expansion valve replaced over Memorial Day weekend. Pressure was building on the low side prior 2 and after that repair. 1 It's also, the pressure builds up downstream of the valve, not before the valve on the smaller line

The only difference now is that since I replace the condenser, there are no leaks in the system and nowhere for the pressure to go so now I guess it's blowing these connections.

The system ran for about 30 minutes while we were trying to figure out how to add the rest of the freon. We had only added a 12 oz can to the system that had been vacuumed out and held for 30 minutes prior 2....

After I blew that connection, I plugged it back in and pulled the vacuum and held it again observing no leaks. I only had half a can of refrigerant left and I attempted to re add it but it really wasn't enough to get the system started but it really wasn't enough to get the system started. After that I had about 70PSI on the low side and the highest I could get on the high side was about 115 or 120.

 

I think your locking seal at that flange is damaged, that line should be able to hold 300-400 psi without blowing off, however your gauge was maxed on the low side so there's no telling how high it actually went.

Do you get a nice audible/tactile CLICK when you reattach the pipe? If not then something is definitely broken on it. You also shouldn't be able to pull it apart by hand but I suspect you will be able to now that it's blown apart a couple times, make sure it CLICKS when you put it together.

As for the pressure issue, high pressure on the low side like that is usually a failed compressor, what did the old expansion valve look like? Was it all crudded up with metal shavings? You can expect to have some metal in it but if it's sludged shut then the compressor probably ate itself for dinner. Anytime the low pressure side gets that high on psi (anything over 60 is high but to max the gauge it's broken high) then the system is either overfilled (you only added maybe a 18 oz so definitely not the cause) or the compressor isn't sucking on that line anymore but rather discharging air from the compressor housing back into the suction side.

The internal pressure relief on the compressor is usually like 500psi so it's not going to blow unless the whole system is on the verge of grenading.

 

So the locking seal on the firewall side was already disconnected prior to me doing any work, and I tried to loosen the other side and try to open that connection by the service port while I was working on it so it is possible that I loosened that connection and left it loose though it did hold.

Yes. I heard it click. I actually didn't push the first one far enough prior to my repairs at first, and had to loosen a clamp to get it to snap it.

The expansion valve, which was replaced just 2 weeks ago,, seemed relatively clean though we had similar concerns,....The compressor has been changed 2 twice in the 3-1/2 years I've owned the car.

I also see the potential for the expansion valve to be the issue, but this line that popped, is on the outlet of the valve....wouldn't that mean that the blockage would have to be upstream of it? Somewhere between the valve and the compressor?

 

The low pressure side is basically the suction side of the compressor though, It's sending all it's pressure out to the high side and the refrigerant is getting sucked back in through the low side. Both sides can EASILY handle 200+ psi, when you're pressure testing the system you open both the high and low side and fill everything to 200+ psi. If it's building pressure on the low side like that but the high side isn't moving it's almost always an internal failure on the compressor.

You can test for blockage pretty easily though, disconnect the compressor line set, hook the manifold back up to both the high/low sides, put air or nitrogen on the suction side of the manifold then open the low/high side one at a time. It will blow out of the compressor line set, use your thumb (with a glove if using nitrogen because it can get really cold really quick sometimes) to cover up the lines one at a time and let the air blow out of the other line. If you can't hold your thumb over the line then there is blockage somewhere. Remove lines and blow them out with air one at a time to find out where it's at.

I've seen expansion valves break and send pieces down the line which can clog it up.

If the line blows air out both sides then the problem is the compressor.

Seems odd that it's eaten 2 compressors though? Did it eat the first one and send a bunch of metal down the line? If so then the entire system needs to be replaced, compressor, condensor, evaporator, dryer. You can reuse the lines but they need to be washed out very well to remove all the metal. You'll never get the metal out of the condensor/evaporator so don't bother. The dryer is a wearable item that usually gets replaced with every compressor swap anyways, plus they're cheap. Usually the entire kit will cost like $400-500 unless you have the condenser that is built onto the radiator then it's an extra $150 or so.

Is the system getting vacuumed down to remove moisture before adding R134A?

Are you adding the correct viscosity of oil and the correct volume of oil when refilling? Did anyone add oil to the previous 2 compressors?

Eating that many compressors in that short of a time frame means something is being done terribly wrong.