Hi, I recently bought a 2004 (late model 2003) Expedition 4.6l. Wouldn't start and it turned out to be the R303 relay issue. ($22 later, runs like a champ!)
The previous owner told me that the ac didn't work. I hooked up my gauge set to it and found that there was no pressure/no refrigerant in it. Almost as if it either leaked down completely or was evacuated previously and never replaced. The previous owner told me that he had it looked at several years ago and couldn't remember what they did but he didn't have it fixed. I pulled a vacuum on it and it had no issues and held a vacuum with no trouble. I went ahead and got enough R134a to refill it (54oz for front and rear air) and began to fill it. As expected, the compressor kicked in as soon as the pressure got high enough and cycled normally until I reached about 48oz. I finished filling it to right at 54oz using a scale with the last can. Sadly, I didn't think about re-adding oil... Now looking back, I don't know if oil came out with the previous owner, and the R134a that I used was straight refrigerant without oil. In doing some reading online, some folks said as long as no major components were replaced, you shouldn't need to add oil. Others said add 1 oz if recharging a system from vacuum. Would it be wise to get an oil charge can with the proper PAG oil and add that or have I passed that point? The system is running great and I'm getting normal pressures on the high and low side and the compressor isn't making any noise at all. (other than normal) It appears that it's the original parts on the truck so I'm sure it's seen better days but I'd like to keep it working as long as possible before I have to swap parts. I really appreciate any insight you can give.
The previous owner told me that the ac didn't work. I hooked up my gauge set to it and found that there was no pressure/no refrigerant in it. Almost as if it either leaked down completely or was evacuated previously and never replaced. The previous owner told me that he had it looked at several years ago and couldn't remember what they did but he didn't have it fixed. I pulled a vacuum on it and it had no issues and held a vacuum with no trouble. I went ahead and got enough R134a to refill it (54oz for front and rear air) and began to fill it. As expected, the compressor kicked in as soon as the pressure got high enough and cycled normally until I reached about 48oz. I finished filling it to right at 54oz using a scale with the last can. Sadly, I didn't think about re-adding oil... Now looking back, I don't know if oil came out with the previous owner, and the R134a that I used was straight refrigerant without oil. In doing some reading online, some folks said as long as no major components were replaced, you shouldn't need to add oil. Others said add 1 oz if recharging a system from vacuum. Would it be wise to get an oil charge can with the proper PAG oil and add that or have I passed that point? The system is running great and I'm getting normal pressures on the high and low side and the compressor isn't making any noise at all. (other than normal) It appears that it's the original parts on the truck so I'm sure it's seen better days but I'd like to keep it working as long as possible before I have to swap parts. I really appreciate any insight you can give.