Automotive Air Conditioning Information Forum

Backstory:

Hi everyone, I replaced my a/c compressor in my '06 Navigator with an aftermarket compressor a couple of years ago. I removed everything down to just the line sets, flushed the lines, dried the lines, and put everything back together with new components (compressor, condenser, drier/accumulator, muffler, expansion valves, evaporator cores.... even new blend door motors after tearing the the front and rear plenums apart to ensure everything was in proper operation. I did a deep vacuum (4 hours, using a 6.5 cfm pump), will with the proper amount of PAG 46 oil (7 ounces), and 3.6 lbs of refrigerant (also the proper amount). I couldn't muster better than 42 or degrees outlet temperature, after confirming no heat was mixing in the plenum, flow to the heater core was cut off, and the recirculation door was completely shut. At idle on warm days I had to drive for 20+ minutes at highway speed with the A/C system on full-blast to start blowing cold air, and when I would come to a stop the outlet temperature would increase 10+ degrees. We tried adding a little more refrigerant, taking some out.... but nothing allowed the system to perform very well. Myself and several other came to the conclusion that the aftermarket compressor must be junk.


Current Issue:

I recently ordered a brand new Motorcraft compressor. I went to install it on Friday, and after un-boxing it I noticed that thought the pulley turn freely by hand, I could not turn the clutch by hand. At all. I read that this can be considered normal for some new compressors (which still has me concerned...), so I decided to install it. I poured 4 ounces out of my current compressor, so I drained the new compressor, and re-filled it with 4 ounces of PAG 46 oil. I did manage to spill a little oil on the compressor pulley and apparently didn't get it all off with I spray the compressor with brake parts cleaner, because the several times I started the engine up after installing the new compressor I would get a quick, short squeal that would immediately go away.

Yesterday (two days later) my friend used his Snap-On A/C machine to fill the system with refrigerant. We got 2.6 lbs in and the machine had some sort of error (I didn't see what it was), but after fiddling with the machine for a couple of seconds he was able to add 1.0 more lbs of refrigerant. Around 60 seconds of the compressor running for the first time I started hearing a subtle chirp, similar to a pulley bearing that's going bad. A few seconds later the chirping turned into a slight squeal, then ramped up very loud, constant squeal just a few more seconds later. I then immediately turned the A/C off. The squeal quickly died out. I let the car idle for a couple minutes, turned the A/C back on and watched the clutch turning just fine. Then 40 seconds later came the subtle chirp, and ramped right back up to a full-on obnoxious squeal again within 10-15 seconds of the chirps. This time I noticed the compressor clutch fighting to turn-- the serpentine belt was spinning faster than the clutch. I could even smell the clutch material a little.

Our immediate thought was that there must be something wrong with either the internals or the clutch on the new compressor. We went ahead and did an evac on the system and I went back home with the plan of having to buy another compressor.

However, the belt still squeaks for a quick second when I start the engine..... so maybe it's just the oil-contaminated belt that didn't have enough friction to keep turning the compressor as it built more pressure?????

I'm contemplating now whether maybe it's worth removing the belt, spraying down all pulleys with brake parts cleaner really well, installing a new belt, and then getting the refrigerant filled again and see what happens???\ Is anything that I'm describing indicate a bad compressor or clutch??? What would cause the compressor to work just fine for several seconds and then start to squeal, if not the belt not having enough friction to turn the compressor as it built more pressure?? The fact that after letting the compressor clutch idle for several seconds and then engaging the clutch again allowed the compressor to run for around 40 seconds again tells me the internals (pistons) are not locking up. Any solid ideas on this??

Thanks so much!
-Andrew

If my vehicle, just to learn more, (1) I'd pull the belt off the compressor and try turning the compressor with a wrench.

(2) I'd jump the compressor clutch with 12 volt positive wire and see if the AC clutch engaged each time.

I would guess that it might be possible to get oil on an AC clutch surface. But wonder if trying to clean that off could damage the pulley bearing.

Let's wait to see what a real expert says.

Debris?

Why was the compressor replaced?

Why buy another? Won't you get a warranty from your vendor?

Cusser wrote:If my vehicle, just to learn more, (1) I'd pull the belt off the compressor and try turning the compressor with a wrench.

(2) I'd jump the compressor clutch with 12 volt positive wire and see if the AC clutch engaged each time.

I would guess that it might be possible to get oil on an AC clutch surface. But wonder if trying to clean that off could damage the pulley bearing.

Let's wait to see what a real expert says.

Thanks for the reply Cusser! I can certainly check the operation of the clutch with a jumper wire, perhaps I can do that tomorrow. I was wondering if maybe oil got on the clutch surface, too..... and then also wondered about the bearing haha. I'd like to think those seals on the bearings were tight enough to keep that thick PAG oil out of there.... and I didn't spray brake cleaner too generously around that area of the bearing, because I think most of the oil I spilled ran down the side, but hard to say since I'd have to fault myself for not looking closer at that. I may have to just get a much closer look at the clutch surface and see if I noticed an residue or anything. Since I did smell clutch material, that makes me think you could be right about the clutch being what was slipping.... maybe not so much the belt only.

Tim wrote:Debris?

Why was the compressor replaced?

Why buy another? Won't you get a warranty from your vendor?

Thanks for the response Tim. I have no yet cracked any lines back open to check for debris... but there was no debris from the last compressor since it didn't experience any lock-up or anything. Compressor was replaced because nothing else explained the problems I was having after installing it. Check the first part I typed about the back story on the situation..... but the system basically wasn't performing well at all. I didn't get a replacement because the compressor was installed 2 years ago (probably had a 1-year warranty at best) and because I heard of a lot of other people having performance issues with aftermarket units. Also, after just 2 years the pulley bearing was starting to squeal on occasion, so I decided to stop screwing around with aftermarket compressors and get a Motorcraft one back in there.


Thanks again guys!

'06 Navigator and 42-degree vent temps. Not sure what you expect from a large vehicle like this! The coil will freeze at 32 and there is 6 to 8 difference between coil temp and vent temp.

To really help much further. I think listing pressures at idle and 1500 rpm will give a better picture.

Ford Scroll is not the best compressor.

Not all manufacturers are the same. I love it when I hear I read these are good or these are bad. 95 percent of the time is due to an improper repair more than a crappy aftermarket compressor.

AGrayson84 wrote: I couldn't muster better than 42 or degrees outlet temperature

Agree with Tim - that's good vent temperature.

Was on the phone with our compressor vendor for another reason. Asked about these compressors. I was informed they either blow a hole in the side of the compressor and or toss tons of debris in the system when they fail. So a slap on replacement of a compressor could be an issue. And pressure readings and the amount of refrigerant added could help give a better picture.

Hi Tim and Cusser. I guess, the bigger picture is that I could only see that low of a temperature on this truck's absolute best day. That's under 85 degrees ambient temperature, after blasting down the highway for 20 minutes or so. On a hotter day, things were so much worse. Or even on an 85 degree day.... if I didn't get the truck moving down the highway, it would never cool down. I could literally sit at idle, in the shade, for over an hour with the A/C blasting on an 85 degree day and I would be lucky to get 55 degrees outlet temperature. On a 90+ degree day, I'm sweating in the truck until I can get thru 25 mins of traffic and hit highway speeds. And as soon as I could muster 50 or so degrees outlet temp on a 90+ degree, while barreling down the highway, within a few moments of slowing down the outlet temps would raise up to around 65 degrees. Some people I've explained all of this detail to don't see anything wrong with that. The '98 Expedition I owned would freeze you out of the cabin within just a few mins of running the A/C on the coldest setting. Same size cabin, also with a rear A/C system. Probably nearly the same components in the A/C system on the '98 Expedition/Navigator. I've never had a vehicle struggle so hard to supply mediocre outlet temperatures. I've owned around 17 vehicles in my life, and a lot have been 90's and early 00's Fords.... and have ALWAYS gotten no less than 38 degrees outlet temps on a 90+ degree day, where this thing can only provide 50 degree outlet temps on a 90+ degree day, after running full-blast while going down the highway for a bit. Something just didn't make sense. And again, after flushing the lines and blowing them dry (with dry air), installing new condenser, compressor (drained all of the pre-filled oil), drier/accumulator, muffler, evaporators, expansion valves, etc......... I did a several-hour vacuum with a large vacuum pump, pulled 30 inHg within a few minutes, and held it for several hours before deciding there was no leak. We've used 2 different Snap-On A/C machines to inject the 7 ounces of PAG 46 oil, and 3.6 lbs of R134a refrigerant.... both exactly what the book calls for. I don't see where, in my scenario, anything was done incorrectly. Several friends that do A/C work have confirmed that I truly did things the absolute best way possible, but maybe there's something we're all missing??? if so, I have no idea what.

As far as pressures go, it has been a while since I checked them, but here are a couple of threads regarding my issues, where I've posted pressures. I have pictures, and even videos of some of things:

https://www.autoacforum.com/viewtopic.php?f=3&t=1533

https://www.autoacforum.com/viewtopic.php?f=3&t=1780

Thanks again gents!

I did not read all of your notes. Let's start over. Run vehicle at 1500 RPM, doors /windows open. Set system on max cool. After 15 minutes. is the input and output tubes of front evaporator cold and about the same temps? If so, the front cooling/refrigeration system is working. Start looking at air distribution (blend doors) Clamp off heater lines. What color is your vehicle? Is it in the shade? Pressures low and high side? Does high side drop when misted with a hose?

Hi Doug, the symptoms I was describing were before I replaced the compressor a few days ago. I had gone as far as clamping of heater core lines, and I don't recall temperatures of the evaporator cores but the lines leading off them, nor the cores themselves, were getting very cool. Blend door motors were all replaced with new Motorcraft ones, and I confirmed mixing door was sealing off heat in the plenum (even though the heater core lines were clamped off), and the recirc door was completely sealing off outside air. The vehicle is a light silver, and the system didn't seem to perform any better in the shade. Even at night time on nights where it was over 85 degrees and a little humid, if I let the truck idle for several minutes the outlet temps would increase at least 10 degrees. I never did get around to misting the condenser unfortunately. But this problem existed on the original equipment, as well as the replacement parts.... and nothing in regard to air flow has changed on the vehicle. I even replaced the fan/clutch assembly, and when that didn't help I added two 14" puller fans to the back of the condenser, and that would maybe give me 1 degree better cooling if I was idling. But even the newest condenser is still clean of debris and all... no obstructions or anything.

Anyhow, with the new compressor that this thread is about.... I was able to turn the clutch by hand today. I also turned it several times over with a ratchet and seemed fine.... though there is a little bit of a squeak when turning the compressor. Not sure if it's normal or not on a compressor that doesn't really have any time being used just yet, aside from a couple of mins tops.

Turning the compressor with a ratchet:
https://www.youtube.com/watch?v=32BHqYoC3LY

Turning the compressor by hand:
https://www.youtube.com/watch?v=HcMKeu9kKQw

I did go ahead and use some good quick-dry degreaser on all pulleys, and the clutch area of the A/C compressor. I put a brand new belt on and brand new Motorcraft tensioner and pulley (even though I just replaced that 2 years ago). No more squeak when I start the engine up, so going to take it to my buddy again tomorrow to see if we have the same problem when we re-fill the system to spec and kick the compressor on. I'll take a video of whatever happens!