95 Ram AC Freon Low
tman
07-26-2004, 07:56 PM
The refrigerant is low on my 95 Ram 1500 with the 360 engine.
I have some DuPont R134a, which is what the truck calls for, but the mechanic at the dealer said, “Mopar Freon only, it has sealants that keep the system performing well.”
Is the mechanic right? If so I’ll buy the mopar stuff, but whats the capacity of the compressor?
I have some DuPont R134a, which is what the truck calls for, but the mechanic at the dealer said, “Mopar Freon only, it has sealants that keep the system performing well.”
Is the mechanic right? If so I’ll buy the mopar stuff, but whats the capacity of the compressor?
fredjacksonsan
07-28-2004, 09:23 PM
Sounds like dealer gibberish to me. You can get the same additives at your local xyz parts store; I've got an older vehicle that was converted from the R12, all the old stuff had leaked out. One can with sealer (amount according to instructions) then filled up the rest of the way, still blowing cold 1 1/2 years later.
tman
07-31-2004, 02:13 AM
I think the system is just low because it short-cycles and the air gets a tiny bit cold. Can I add without putting in and sealer? My duPont stuff says not to mix with any other refrigerant, can I ignore that?
fredjacksonsan
07-31-2004, 06:12 AM
The short cycle is a real good indicator of low freon. I don't know why you shouldn't mix the two, maybe they mean don't mix 134 with 12, which does make sense. I'd think that the brand name shouldn't matter, after all R-134a is R-134a and Dupont holds the patent.
As far as capacity, you could always use the backyard mechanic guideline of filling from (small) cans until the system won't take anymore. Or check the service manual and see what the pressure should be (if you have the pressure guages) on either side of the compressor.
As far as capacity, you could always use the backyard mechanic guideline of filling from (small) cans until the system won't take anymore. Or check the service manual and see what the pressure should be (if you have the pressure guages) on either side of the compressor.
tman
08-01-2004, 03:57 PM
Also, what would cause a small metal to metal grinding noise in the compressor. It's like the AC clutch is rubbing against the spinning pulley. If I play with turning the AC on and off, I can usually find a good spot and the noise goes away.
If Dupont holds the patent, then all the r134 has to be the same, regardless of whose label is on it. I just need to buy the tool that adds freon.
If Dupont holds the patent, then all the r134 has to be the same, regardless of whose label is on it. I just need to buy the tool that adds freon.
fredjacksonsan
08-01-2004, 09:45 PM
Alot of time you can pick up the kit with hoses right next to the coolant on the shelf @ auto parts store. As far as the compressor, can't be sure. Alot of older (70's) mopars had a grindy noise in the compressor; how loud is it?
tman
08-01-2004, 10:45 PM
loud enough to be heard at a stoplight, but not diring a drive. If I hold a long screwdriver to the compressor, and my ear to the screwdriver, there is nothing out of the ordinary with it.
fredjacksonsan
08-03-2004, 11:19 AM
I would think you could continue driving. On most of the older vehs I've owned, there was some amount of compressor noise, which got louder as the vehicle got older. As long as there are no grinding bearing noises (and you'll know when you hear that) I wouldn't worry.
SwampNut
08-03-2004, 02:09 PM
First off, that mechanic is either a moron or a liar. Either way, time to start avoiding him. There are definitely no sealants in there, in fact, sealants should almost never be used in a A/C system; they are really evil.
You should realize that you're playing around with one of the most complex systems in a vehicle. A/C can't just be "close enough." There's a fairly fine line between "low," "good," and "compressor failure." At the very least you should get a basic single guage with adapters for both high side and low side, and test both. There are lots of guides available on the internet that tell you what the ranges should be. This is the only way you'll know if you truly do have a low charge, and not some other disaster waiting to happen.
You should realize that you're playing around with one of the most complex systems in a vehicle. A/C can't just be "close enough." There's a fairly fine line between "low," "good," and "compressor failure." At the very least you should get a basic single guage with adapters for both high side and low side, and test both. There are lots of guides available on the internet that tell you what the ranges should be. This is the only way you'll know if you truly do have a low charge, and not some other disaster waiting to happen.
tman
08-03-2004, 04:41 PM
Well I naturally intended to check the pressure BEFORE adding any! I have the Chrysler Service Manual for the vehicle, and it should list the ideal pressures. It's definatly not a bearing going, but more like metal-metal contact between the pulley itself, and the compressor clutch.
SwampNut
08-03-2004, 04:57 PM
It might, not sure. I know most of the aftermarket manuals now say they don't provide A/C tech details because the home mechanic shouldn't mess with it.
Really your best bet is a discharge, vacuum, and refill by WEIGHT not pressure. The capacity should be listed on an underhood label. On my '99 1500 with the 360, it says 2.0 pounds. Auto Zone will give you free rental on a vacuum pump with a $200 deposit.
Once you draw a vacuum for 30 minutes, you can be pretty sure any moisture is removed, and you're starting from a known base. Then diagnostics will be useful if it still has issues.
Really your best bet is a discharge, vacuum, and refill by WEIGHT not pressure. The capacity should be listed on an underhood label. On my '99 1500 with the 360, it says 2.0 pounds. Auto Zone will give you free rental on a vacuum pump with a $200 deposit.
Once you draw a vacuum for 30 minutes, you can be pretty sure any moisture is removed, and you're starting from a known base. Then diagnostics will be useful if it still has issues.
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