sneakingfart
OBS Enthusiast
Hi Everyone,
I have a question, and hopefully you all will tell me that this is just how the AC these trucks is supposed to function. A little back story, since I am new here. I was able to get a 1999 Suburban in non-running and poor cosmetic condition for free from a relative who didn't want it. Long story short, I really like these old trucks, but have no experience with them. It has now been cosmetically restored and all the mechanical issues sorted, and it is a completely reliable driver. The AC was not functional when I got it, so I have no baseline, and the leak was in two places. The previous owner screwed up the high pressure Schrader valve on the compressor manifold, and the compressor itself was leaking where the 2 parts of it meet in the middle. I replaced the compressor with the same Delco unit, the accumulator, orifice tube, high and low schrader valves, and all easily reachable o-rings. The accumulator was stuck where the evaporator core pipe enters it, and I did end up crimping the pipe somewhat while trying to remove it, but there are no leaks that I know of. In the end, the system held vacuum for over an hour with no drop, and was refilled with the right amount of r134A, given that I have rear AC, it took 64 Oz I believe. But I put in whatever was on the sticker on the accumulator for rear AC equipped trucks. Compressor oil was also added. I have never used any stop-leak (but I can't speak regarding the previous owner), and I put in r134A with dye. No obvious leaks are present.
Now, the AC blows cold when the ambient temp is in the low 80s, and I get around 40 degrees on the center dash vent. When ambient temps are in the 90s and I am driving, I get around 45 to 48. Problem is, when I am idling in traffic and I have both the dash and rear AC running, the temp is closer to 60. When moving at speed, it will eventually drop to the mid-high 40s. If I turn off the rear AC and slow down the fan on the dash AC, the temps are even colder. My only frame of refence is my 2022 BMW X5 with front and rear AC, and it's much colder at idle. Of course it has electric fans on the condenser. Ultimately, I need to know if this is normal behavior for these trucks, or is there something I am missing? Engine fan clutch is good. I checked pressures today, at 85 degrees ambient temp with the front and rear AC fans at max speed, recirculate on and windows and doors closed, and I got 40 PSI on the low side and 225-230 on the high. Seems fairly appropriate I think. Thanks everyone for your help.
I have a question, and hopefully you all will tell me that this is just how the AC these trucks is supposed to function. A little back story, since I am new here. I was able to get a 1999 Suburban in non-running and poor cosmetic condition for free from a relative who didn't want it. Long story short, I really like these old trucks, but have no experience with them. It has now been cosmetically restored and all the mechanical issues sorted, and it is a completely reliable driver. The AC was not functional when I got it, so I have no baseline, and the leak was in two places. The previous owner screwed up the high pressure Schrader valve on the compressor manifold, and the compressor itself was leaking where the 2 parts of it meet in the middle. I replaced the compressor with the same Delco unit, the accumulator, orifice tube, high and low schrader valves, and all easily reachable o-rings. The accumulator was stuck where the evaporator core pipe enters it, and I did end up crimping the pipe somewhat while trying to remove it, but there are no leaks that I know of. In the end, the system held vacuum for over an hour with no drop, and was refilled with the right amount of r134A, given that I have rear AC, it took 64 Oz I believe. But I put in whatever was on the sticker on the accumulator for rear AC equipped trucks. Compressor oil was also added. I have never used any stop-leak (but I can't speak regarding the previous owner), and I put in r134A with dye. No obvious leaks are present.
Now, the AC blows cold when the ambient temp is in the low 80s, and I get around 40 degrees on the center dash vent. When ambient temps are in the 90s and I am driving, I get around 45 to 48. Problem is, when I am idling in traffic and I have both the dash and rear AC running, the temp is closer to 60. When moving at speed, it will eventually drop to the mid-high 40s. If I turn off the rear AC and slow down the fan on the dash AC, the temps are even colder. My only frame of refence is my 2022 BMW X5 with front and rear AC, and it's much colder at idle. Of course it has electric fans on the condenser. Ultimately, I need to know if this is normal behavior for these trucks, or is there something I am missing? Engine fan clutch is good. I checked pressures today, at 85 degrees ambient temp with the front and rear AC fans at max speed, recirculate on and windows and doors closed, and I got 40 PSI on the low side and 225-230 on the high. Seems fairly appropriate I think. Thanks everyone for your help.
