What, or Who Killed my A/C Compressor?

[Hoofhearted]

Greetings Fordlings,

I understand this is probably a technical issue, and may not be a question for Ranger owners, but I'll go ahead and shoot.

Last summer, my AC worked fine- no problems.

Next spring, it no longer blew cold air.

I took the Ranger in to have some repairs and maintenance done on the front end, told them to take a look at the ac too.

I gave them permission to charge it up if that's all it needed, but to not do any extensive repairs without first consulting me.

I now understand, it was ignorance on my part that lead me to believe a simple charging of the unit might fix the problem... but I digress.

They called and said front end was done, but that I would need a new compressor- at which they quoted me in excess of $600 to complete the install.

I kindly told them No Thanks, and never thought to ask, "How" they were able to come to their prognosis of a bad compressor.

I'm just wondering if perhaps the AC stopped working due to a leak which had formed at some time after the end of last summer.

If this is the case, it seems the compressor would have a safety switch to prevent it from kicking on.

I understand that sometimes, things just crap out, but there often is a simpler explanation.

I don't distrust the shop that worked on it, but I would not be shocked to learn it was an error on their part- either misdiagnosing, or perhaps even causing the damage themselves by use of improper technique.

Does anyone have any thoughts or experience with these compressors,,and Are they prone to failure and replacement?

Hoping to gain a bit of insight here.

Thanks!

'02 Ranger 4.0

 

[97RangerXLT]

As refrigerant leaks out the remaining refrigerant loses ability to carry the lubricant to the compressor. There is a low pressure cut off switch to protect the system. Maybe the shop determined that the compressor was the source of the leak. In this case they would be right, a new compressor would be needed. You would also need to replace the accumulator and orifice tube, plus flush the lines and the evaporator and condenser. Then they would need to pull a vacuum on it and recharge the system.

$600 actually seems like a pretty good deal for that. Maybe even a tad low.

AJ

Sent from my SCH-I535 using Tapatalk

 

[adsm08]

As stated, as the system leaks it loses the ability to bring the oil back to the compressor, and it will pool in the accumulator. This becomes the equivalent of running an engine with no oil in it.

There is a low-pressure cut out switch, but since A/C charge levels are based on weight, and the switch works on pressure, which can change very little if the temp goes up as the mass of the charge goes down, they don't always protect the system, because protecting the system is not the primary purpose of the switch.

Since you have an 02 I assume this is the 4.0 SOHC, and I have seen a number of spontaneous compressor failures on them over the years, seemingly not triggered by low charge, or some other failed part.


Although it is also possible that the compressor has not failed internally but that the clutch has worn out of the field coil has died. Either of those failures would also warrant compressor replacement and not be related to any other failure.


I would go ask them why the compressor needs replaced. An uninformed customer cannot make an informed decision. When I tell one of my customers what is needed to fix their concern I am up front about all the parts needed, why it's needed, and why the part failed, if I know exactly why it failed. I am also more than willing to tell them if I don't think their vehicle is worth the money needed to repair it, even if it means I might lose the repair. Even though I work at the dealership I get $0.00 if they buy a new car instead of fixing their old one.


Also, if they want to replace the compressor due to an internal failure and they don't want to replace anything else, or flush the system, the repair will not be effective. There are several lines and an orifice tube that must be replaced, along with flushing of the system, for the repair to be effective if the compressor failed internally. Otherwise there are still bits of compressor floating around, like little assassins, waiting to kill the new one. It's almost like spinning a bearing in the engine and then putting a brand new engine in but using the old oil filter.


Also, you can ask us all the in-depth technical questions you want about any car you like. We aren't just Ranger owners, we are TRS. If someone here can't answer your question then the answer must not exist.

 

[straycat]

^^^What they said. This happens in a lot of different types of A/C units. One thing I do know is that you need to use that A/C once in a while to circulate the unit and to prevent the seals from drying out. I made that mistake on one of our older Subaru’s some time back. I just liked the windows down a bit in the summer and I did not use the A/C. One day my wife took the my Subaru to school while I had her car serviced. It was a really hot day and when she came home she was drenched in sweat and said the A/C is blowing hot air. I worked on it for a while and then took it to our shop. They asked me if I turn it on once in a while and I said hardly ever. They said you need to run it every once in a while to keep them from having any issues. The Subaru had about 60,000 miles on it at the time. It cost about $300 to fix it. Since I listened to that A/C tech I have never had any A/C issues with any of our vehicles. I just turn them on once in a while and do it even in the winter.

 

[85_Ranger4x4]

I just turn them on once in a while and do it even in the winter.

Probably not a help for you but in northernish climates the compressor runs with the defroster in the winter so it still gets exercised.

 

[Hoofhearted]

What if anything, can I do from my modest garage to troubleshoot?

I still have plenty of time left on service gauges and vacuum pump from autozone.

I wanted to pull a vac check, but could not locate both the low and high pressure valve caps.

Could someone tell me if the valve stem in the pic below is coming from my high or low pressure line?

I slowly began to unscrew the cap and it started to give an ever so slight pffff before I quickly tightened the valve cap again.

Does this mean the system has charge and indeed is a sign there are no leaks?

 

[97RangerXLT]

That is your high pressure side.

the low pressure side valve is probably on the accumulator/dryer.

if you hear refrigerant escaping when you loosen the cap, that is probably normal if it is a small "pff" when you take the cap off, especially if the cap has not been removed for a while. if you hear it escaping or see bubbles coming out of the valve then you probably need new valves. they are cheap, but you need to evacuate the system to replace them.

You can't pull a vacuum on the system unless there is no refrigerant in it. if you have some rented gauges from autozone, close all 4 valves on them before hooking them up, and make sure that the hoses are firmly seated onto the high and low side ports. blue to low, red to high, and they will not interchange, so you shouldn't have any issues getting them mixed up.

hang the gauge set from the hood and route the hoses away from the fan and any moving part of the engine

Open the valve on the low side right next to the service port Do NOT open the low side on the manifold!! Open the high side valve next to the service port, again Do NOT open the valve on the manifold!!

you should have about 60 lbs pressure reading on both gauges. if you have less, you may not have enough refrigerant in it for the system to cycle. if you have more than 90 on a hot day, you may have too much charge in the system, and will need it to be evacuated by a shop to reclaim the refrigerant.

Start the truck. turn the a/c on max. if you have more than 60 lbs static pressure, the clutch should turn on and you will see the low side drop to as low as 25 lbs to around 45 lbs, depending on outside temp. the high side will go up to above 100lbs to even 250 lbs or more depending on how hot it is outside. (pulling these numbers from my foggy memory, so they could be off... I will post a link to an A/C how to that I wrote last year when I redid my A/c, it has some pressure/ temp charts in it to give you a closer idea of what you should see on the gauges.)

If you are seeing over 300 lbs on the high side, you have problems, and will probably need to pull the system apart and see why it is doing it. chances are that is the reason the shop told you your compressor was junk, you got an extremely high reading on the high side, and a real low reading on the low side, which says that your orifice tube is plugged up from little gunk and parts of your compressor...hence the need for a new compressor and orifice tube plus system flush.


also, make sure that your blend door is on cold and not letting engine heat into the cab. sometimes it will break and stick open or partially open.


AJ

 

[97RangerXLT]

And as promised, the link to the a/c resurrection how to:

http://www.therangerstation.com/forums/showthread.php?t=144542

AJ