When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Big Dummy's Diesel Ex Update - Fried my new AC compressor.
Hi everyone,
Last weekend my son and I finished buttoning up the new engine on my 2005 6.0 Excursion. We replaced just about everything forward of the firewall, including all of the AC components. I was going to wait until this weekend to replace the rear evaporator and expansion valve, unpop the drier ports, connect everything, add oil, pull a vacuum, and add gas. Unfortunately, a couple of days ago, I took the EX for a quick spin and, thinking that the clutch would not engage because there was no gas in the system, I hit the recirculation button to keep the fumes from the road out. This must-have actuated the compressor clutch because about a few minutes later, when I got home, I had smoke coming from that general area. I let the car cool down and when I was sure nothing was catching on fire I left it for another day. Today, when I went to go check it, I started the Ex and, with the AC off, there was no problem but, as soon as I hit the AC button, I could hear the engine get loaded down and what sounds like the AC clutch slipping loudly. I'm pretty sure I seized the AC compressor. I'm a dummy.
Here's my questions:
1) In other vehicles and heavy equipment that I have worked on, the AC clutch won't actuate if the system isn't pressurized. Is that not the case for the EX?
2) Should I be checking for any shorts, etc that might keep it from disengaging the AC when there is no pressure in the lines?
3) Should I remove and clean the two lines that come from the compressor? I never connected the one that goes towards the evaporator core but, I did connect the line that goes to the condensor.
Thank you for all of your advice, I sure have learned quite a bit just from reading all the stuff on the forum.
Something doesn't seem right, there SHOULD be a low pressure cutout switch, probably on the receiver drier. Preventing the compressor operation. #13 is the low pressure switch in close proximity of the drier. If the system was open a very short time, (which it sounds like it was not) then there will be enough Freon left in the oil throughout the system to slightly re-pressurize the system, therefore tripping the switch. A V-10 I pulled the suction hose from let out an ounce or more when I opened the connection up, and I heard the pressure switch click. As far as oil, my 7.3 OE compressor does not have a reservoir/sump, the drier has a siphon at the bottom to pick up oil and distribute throughout the system. This is despite the instructions and shop manual from Ford stating to add oil to the compressor. The part numbers for yours and my drier are the same.
Something doesn't seem right, there SHOULD be a low pressure cutout switch, probably on the receiver drier. Preventing the compressor operation. #13 is the low pressure switch in close proximity of the drier. If the system was open a very short time, (which it sounds like it was not) then there will be enough Freon left in the oil throughout the system to slightly re-pressurize the system, therefore tripping the switch. A V-10 I pulled the suction hose from let out an ounce or more when I opened the connection up, and I heard the pressure switch click. As far as oil, my 7.3 OE compressor does not have a reservoir/sump, the drier has a siphon at the bottom to pick up oil and distribute throughout the system. This is despite the instructions and shop manual from Ford stating to add oil to the compressor. The part numbers for yours and my drier are the same.
It had to have been open..."Fried my new AC compressor"
Let me explain a little further:
The front evaporator, condenser, filter/dryer, compressor, and lines are new. I never removed the caps from the dryer so that it would not be exposed to the atmosphere/moisture before I closed it up to add gas and oil to the compressor. The line from the compressor to the condenser was connected but the line from the compressor to the dryer and evaporator were not plugged together. I did, however, plug and tape them to keep them clean. My understanding was that there was a cut-off switch that, because the system was not pressurized, would keep the compressor clutch from engaging. Unfortunately, my enthusiasm got the better of me and I decided to take it for a quick test ride (new engine and all) and I didn't verify whether the clutch would engage beforehand.
Thor363:
---I have to ask, did you prefill the compressor with PAG oil to the recommended amount and also change the inline filter?
I had not added the PAG oil yet, my plan was to first (today) replace the rear evaporator and expansion valves and clean out the lines. I assumed (wrongly) that the clutch would not engage since the system was depressurized. The filter dryer is new and in place, but I have not uncapped/plugged it in. My intention was to do that all today when I buttoned it all up. Of course, now I have to add change the compressor. I'm a dummy; I have no excuses
Excursion_01:
Thank you for the diagram. That's what I thought to but, seeing as it engaged the clutch, something's got to be going on. As far as I can tell, there shouldn't have been any pressure or oil in any of the lines forward of the firewall. I am heading to my garage right now to replace the compressor and I'll post as soon as I have some more info.
Thank you again, I really appreciate the help.
Big Dummy
At first glance, I noticed that the suction line to the compress which, I had not connected to the dryer, yet, had blown out the plug and the tape and there are little bits of aluminum around the area where it blew out. Looks like I'm going to have to pull out the compressor lines and clean them out and check to see if the debris made it to/past the condenser.
Does your new drier not have the low pressure cut out switch? If so, without disturbing the drier caps, what happens if you OHM or continuity through the switch spades with it's plug removed? Is the switch showing closed?
Hi everyone,
I apologize for not writing sooner. I didn't get a chance to work on the excursion again until today.
01_Excursion You are right, the low side pressure switch was reading closed. My guess is that it was internally shorted. I went ahead and replaced both the Low and High side pressure switches. The plugs looked good so I left them as-is.
Question:
I went ahead and put 4 oz of PAG oil in the compressor. I understand that the entire system takes 14oz. I've replaced all of the AC components that are forward of the firewall and I am going to replace the rear evaporator core and expansion valve. How should I go about adding the remaining 10 (fl?) oz after I replace the remaining components and blow out the rear lines with laquer thinner and filtered air?
Typically you measure the amount of oil that remains in a replaced component, therefore allowing you to add the subtracted amount to the new component. Otherwise the service manual states an approx amount to add to each component replaced if there is no reference point.
OK, that makes sense. Prior to installation, I did my best to clear any oil that was in the new compressor (it was close to 4 oz) and I replaced the 4oz with new oil so that I knew what was in it. I don't have a service manual to tell me the amounts of oil that should be in each component. Is there one online that I could refer to? I don't mind paying for an FSM, if there is one available, I just haven't come across one for sale.
Thanks!
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
