After noticing that my air conditioner doesn't work as well as it used to I recharged it with a auto parts store R-134A can. Once I did this the the air immediately became cold and worked just fine. I did this in the winter as I cycle my system every so often so that it doesn't go bad.

Now I have noticed that it doesn't work at all and I don't really want to waste another 30 dollars on a can of 134A when I am fairly confident that I have a leak somewhere. I am assuming that is an O ring in the compressor, but I have no way of being sure of this. it very well could be somewhere else in the system.

Now when I turn the air on the compressor will intially engage then disengage itself soon there after. It will cycle like this continuously.

Does the truck have sensor telling the clutch to disengage when there is low R-134A??? What other problems could it be?? Has anyone else ran into a problem like this??


Thanks in advance,

Brett

 

Sounds like you are low on charge. You can get refridgerant in cans at the auto parts store for 6-8 dollars each. I would put another can in and see how long it takes to leak out, because it could get extremely costly chasing a small leak. If its real small it might go a year between charges.

 

You can also get some UV dye to put in there and it will show up under a black light where it's leaking. Or find a buddy with a leak sniffer. Hope it's not your evaporator coil! Dodges are known to have problems with them. Not a real expensive part, but a headache to change. If you do change it, better do the heater core while you're in there.

 

I added a can of 134a w/sealer and some ester oil.. Yes the compressor will cycle on and off if the pressure is low.

Remember.......low pressure = leak somewhere

 

I went through all this. First time it was under warranty. They did the dye thing and found nothing. I had to pay for a re charge. It lasted a month. Then I went to a specialty AC place. They tore apart the under dash part, checked out the compressor and all lines-the whole system. It turned out there was a very small leak around the seal on the compressor main shaft. Very difficult to diagnose. Between the housing and the pulley. New compressor.
It was an expensive lesson in AC-dum.
The result has lasted well for 2 years now.
regards, as always, jefe

 

R134a molecules are small enough that even freightliner states it is acceptable to lose up to 6oz of refridgerant through the lines and O-rings every year. The refridgerant also doesn't 'go bad' the way it works is just based off of the ability to absorb heat as a liquid and dissapate heat as a vapor. When you pull down an A/C system for service the refridgerant is reused.

The cans to fill the A/C system yourself may work okay but without using a manifold set you can't charge the system exactly and an overcharged system will have problems as well, such as the compressor cycling too often because the high side pressure switch will trip more often shutting the compressor clutch off to protect the system. You also have to consider that when you lose refridgerant you also lose the oil that lubricates your compressor.

It's best to have the system taken care of with the proper tools, which in most cases is retardedly expensive. The UV dye is the best idea for leak detection I think because in most cases you're going to be able to see when a leak develops by the mountain dew colored oil slick where the leak is.

Most systems have switches or sensors that will shut the system on and off depending on certain conditions. There are sensors on the sides of the system ( high side where it travels from you evaporator to your condensor, and low side where it travels from the condensor to the evaporator) too high of a pressure will shut the clutch off, too low usually engages the clutch. If there system is low though it will be able to see the compressor running isn't building sufficient pressure and shut it back off. It's common for a system without a proper charge to cycle the compressor clutch quite often

Sorry for the long response but I figured I'd try to spread some knowledge on one of the few things I know about

 

I've had the evaporator go bad (about $700) and the low side pressure switch go bad (about $35) at different times. If the compressor is initially cycling on and then going off you are probably low on refrigerant. You can check your low side switch and confirm that R-134a is low by taking off the connector to the low side switch (passenger side firewall vertical bottle - the connector at the top) and shorting the connectors. The compressor should run uninterrupted now (just don't do it for very long since you ARE low on refrigerant!). This just confirms that you are low. Hooking up a recharge bottle with gauge helps show what the pressure is. It should be reading low. Just check it with the engine running and the AC on high/cold to get a good reading....

 

it is more then likely your evaporator is bad. It's a common thing for them in the dodge trucks. I have done a couple of these. If you can get a sniffer or leak detector, Charge the a/c enough so it works and put the sniffer in one of the vents. It will more then likely go nuts when you do that. Mine is bad right now in my truck but seeing as it's not my daily driver, i haven't fixed it. I hate to think of tearing the dash out just to get to the box with the evaporator in.

 

If anyone has replaced these, have you noticed water accumalation/corrosion?

Or is it just poor manufacturing or mouinting?