im planning on recharging my ac, but im not sure how much freon my truck uses. i put in a 12 oz can, just to make sure the compressor still works, which it does. does anyone know how much more i need to put in, or know where i can find out? i have a 99 ram 1500 with the 5.9l v8

 

I think capacity is about 32 oz. There is not much way for us to know how much is in there, but if you put a pressure gauge on it and measure and then check the chartin the FSM, it will give you an idea if you need another can or not. Another ballpark way to decide is to meausre the ac air temp. How cold does it get?

 

it gets cold, but not as cold as it should, i dont think. and it takes like 5 mins to get cold

 

Cold is relative. I worked on my brother in laws car yesterday. he thought his was cold. Measured at 82 degree air temp (96 outside). O brought it down to 66 degress. NOW it is cold.

Got any way to get a temp?

 

yeah, I have to refill mine every year. Its important that when it feels nice and cold to STOP! hah, if you over fill just a little bit it will be back to being warm. 2 summers ago I replaced my fittings because the one i plug a freon can in would leak. I Think it took 2 cans of oil and 2 cans of freon but not sure. I will try to remember where i got this info from.

 

thanks for the info guys. i can put a thermometer in the truck when it gets warmer again, the next couple days should only be in the 60s.

 

Wow.....2 cans of oil is too much oil. The oil does not evap and condense at the same rate as the refrigerant and will over saturate the refrigerant. This will cause the drier to fail eventually, and I have even seen this cause a compressor to lock up.

 

You should not have to add ANY freon in ANY system. A/C is a closed system and if you have to add ANY freon, you have a leak somewhere.

 

As far as I know there is supposed to be about a 40* drop in temperature in a properly working ac system. I'm not sure about the dodge but my car if completely empty takes 6 oz oil and 32 oz of r134. Usually you're looking for about 35-40 psi on the low side but if you're getting close to a 40* drop in temp with 30 psi on the low side I would leave it there. Make sure the a/c is on max and the blower is turned on high when recharging. If it's leaked some oil I would get a can of r134 with an oil charge in it- usually 2 oz oil in the can with the r134.

 

Forty degree drop in temp (from ambient) is a good rule of thumb - on a 100 degree day. It cannot do this all the time - for example, on a 60 degree day the temp will not drop to 20 degrees. This is one area that nearly everyone overlooks, and why the chart is int he FSM. The Delta T is what you are looking for to determine capacity to cool and efficiency of system.

And also, as Crackshot stated, it is a closed system and should not require charging, so if you have to charge one, it is leaking.....Refrigerant does not just wear out or get conusmed.