Just went on a trip to SC. It was hot as hell - 100F most of the trip. The a/c would blow cool (not exactly cold) for a while and then go luke warm (way better than outside but not particularly refreshing) for a while. So I was reasonably comfortable but definitely not cold.

This would happen about every 15-30min where I felt like the compressor had stopped working for a while. I am thinking the compressor is probably limping along and about to die. Usually I thought these things just up and die though. Clogged accumulator? IDK - nothing has been done to the a/c system since 2009 head gaskets.

Thanks for all help - Dan

 

Almost sounds like it's low. I would check my pressures if I were you and go from there.

 

Mine does the same thing. I had the Ford dealer check it. All is good. So I just live with it.

 

yeah i plan to check pressures. I don't have hoses and a manifold though. I hope I don't have to live with it. I'm in FL - this is serious

 

The compressor usually craters and does not just cut in and out.

Now, you might have a bad AC clutch. I had that with my Taurus, but it was the bearings and it froze in place and blew up the belt.

Easiest thing to do to get an idea of your problem is to turn the truck on, put the AC on max, put the fan on max, pop the hood, and then listen for the AC clutch to click on. On max AC and max fan, the AC clutch should be engaged all the time. If it is clicking off and on, that means that you are low on refrigerant. It has a low pressure sensor and the compressor will cut off when the pressure gets low. This is to prevent the compressor from cratering/imploding.

Now, if your truck is like mine, with the compressor at the bottom of the engine bay, you might have to get underneath it to look at the compressor.

Next, if you do not hear the AC clutch clicking off and on, you should pay attention to the AC clutch and see if it is slipping. I am guessing this is not the case because the AC was working off and on while you were using it.

Buy a can of r-134 with the gauge on it if you do not want to spend the money on a gauge set. I did this at first for my Taurus, and then realized that a gauge set and vacuum pump were going to be needed, so I "splurged".

 

I guarantee the orifice tube has got debris in it, meaning it needs to be changed. This also means that you have to vacuum down the system and then change the tube and while your at it change the receiver /dryer. You will have cold A/C then.

 

I have no problem cooling my truck in Fl and it's black. First thing to check is the clutch air gap.

 

guess it is time to buy some gauges. I was worried about that orifice tube - if it is clogged, doesn't that usual mean the compressor is breaking up?

 

Get gauges on it or anything else is a guess other than the clutch. If your high pressure reading builds way high while your low pressure also drops even lower than norm at the same time then I'd suspect clogging screen on the orifice tube. If that's the case pull the tube and inspect the debris. Then make a choice of doing the compressor or not. I'd also do the dryer same time.
There is also a low pressure switch so if the system is a little low it will kick out the clutch too especially at higher rpm. Also if there is low air flow it may ice up and kick out.

 

As already mentioned, the gauges really tell you what is going on with the system and they just make life a whole lot easier when dealing with vehicular AC issues. One of my better tool purchases.

 

Got some PDFs for you to read.
If you find that you need others let me know what you need and I'll
get it posted asap.

EDIT : This may sound funny but have you checked for any DTCs?


Sean <BR>

6.0L Tech Folder

 

Thanks guys - I have some gauges coming. Can't decide if I should splurge on the vacuum pump and other bits too. No DTCs. When it is not so friggin hot it actually seems to work fine

 

Since it only acts up when hot, another thing to check is the condensor. If it clogged up with bugs and dirt the effeciency will suffer increasing the pressures and the high limit pressure switch will kick off the compressor.

 

Autozone loans them out if you don't want to buy one. Just have to pay for it and they refund you when you bring it back.

 

Tools with gauges that are loaner tools I would not trust
do to being dropped a few times without being recalibrated.

I did not read the list of DTCs but if it was dropping out do
to high pressure cut off you would think it would set a DTC.



Sean <BR>

6.0L Tech Folder