Earlier this week my A/C stopped working in my ‘18 5.0. I found a leak in the low pressure hose either at the service port or at the junction to left of it. I brought the truck in to have the low pressure hose and refrigerant replaced. They left me a message today saying I need a whole new compressor. I have never had any issues previously with the compressor and I know that under a low pressure situation, like from having a leak, the compressor won’t run to protect itself, so I’m having doubts. Does anyone have any advice before I call them back tomorrow? I really can’t afford to have to replace the compressor right now.

 

If the hose got a leak and the system let the low side drop to negative pressure, you could have sucked in contamination that damaged the compressor. It's POSSIBLE.

You can always take the vehicle elsewhere for a second opinion.

 

I talked to the service advisor yesterday and he said he couldn’t get the compressor to run, but I’m not sure how he could have tried without charging the system.

 

Not being at the shop, difficult to determine, but hopefully they added refrigerant but then the clutch/compressor won't engage/run to fill to proper weight.
Haven't the slightest idea, as if something was bad or compressor internals shot, I'd think the clutch would still energize and if compressor seized, the belt
would slip around the pulley.
Try to get more info from the shop, clutch engages but compressor won't turn, or clutch doesn't engage at all?

 

The problem here is: we dont know the exact reason why it "stopped working earlier in the week." The leak, could simply have been incidental to the compressor failure or the leak could have caused the failure. Ford vehicles are known to have valve stem leakage and Ford even states some is normal. (Yes I just read that in a Ford service disk I got.)

At any reputable shop, charging and checking the system is as simple as connecting the ac ports to their AC machine and within minutes, its evacuated and recharged to spec.

Was this a Ford dealer? Dealers and techs (based on my recent experiences) are hurting financially, so not all recommendations are warranted. Not sure in your scenario, maybe a second independent shop can review it.

 

But from my understanding, the compressor needs to be operating to draw in the refrigerant, no compressor operation, system can't be fully charged.

 

yes that is true. The tech will know quickly though, either the compressor will start because it has enough in to do so or it wont. My statement was made because I believe you questioned the compressor diagnosis.

 

Was it the dealer? And if out of warranty, why take it to the dealer? They can start the compressor by jumping the low-pressure switch they do it all the time to charge the system. I would not trust a dealer as far as I could throw them. But indy shops can also have low scruples. You'll be out the diag fee if you take it back now but that has to be cheaper than a new compressor.

 

FTFY


To set final pressure, absolutely, but on systems with low pressure limit switches, you have to either bypass that switch or get enough pressure into the system so it won't trip, before you can run the compressor.

One thing I had to do when I worked for Sears was keep an eye on a system I was filling if there were multiple units being serviced. As long as a tank was at least half full, it could fill to required refrigerant weight without turning on the unit. As filling, even with the compressor running was a long, tedious process if we had conducted a repair, we'd just let the tank do it's thing and go do other work for a while. Let it go for too long, you can overfill a system, especially on a hot day, which was about the only time we had AC work to do.

 

This truck doesn't have a low pressure switch, those were last used on the F150 for the 2007 model year.

Starting in 2008, they went to the pressure sensor in the high pressure line combined with the evaporator temperature sensor. No jumping allowed with those.