So I finally replaced my plenum with the thick aluminum one (the old steel one that was on it didnt have any leaks, was sealed nice and strong, so ended up being more of a longevity repair ;(...) Anywho, I got it all replaced and back in and it runs fine like it did before, but now my AC doesn't seem to be blowing cold at all. I can hear the compressor kick on on the AC settings, and I can feel the line under the hood getting very cold, but I don't notice any change whatsoever between the fan and AC modes, prior to this I remember my AC being super cold.

I know I didn't unplug any of the AC lines, as I just laid the compressor out of the way when I did the swap, any ideas what else could be causing this?

 

You’d need to put a set of gauges on it and see what your pressures are.

 

You may have created a slight refrigerant leak when you moved the A/C compressor out of the way to perform the intake repair or a slow leak may have already been in-place, since A/C only really gets run during the warmer months. Like was mentioned, you can put some A/C gauges on it to check the pressures in the system to see if it's low on refrigerant.

 

Does the heat blow hot? What year is your truck?

 

I've got no heat, heater core is bypassed since it was leaking, and im not about to break my ALMOST perfectly uncracked dash to try and replace it haha, but I live in the south, so I haven't needed it at all, only dropped below freezing for a few days awhile back.

Truck is a 2001.

I don't think it has a slow leak in the refrigerant as it was blowing cold prior to replacing the plenum, and the lines are still getting cold like they were before. Its just that cold air isn't reaching the inside of the truck. I'm assuming I would feel SOME change since even if it was low on refrigerant, its cooling the lines, so id expect SOME difference even if it was slight, but there was no difference what so ever.

 

When you are running the A/C, is air actually blowing out of the forward vents as you would expect?

 

Yeah there's been no change in the intensity of the air in relation to its fan speed settings. The only difference is I don't notice it getting cold when its on AC :/

 

Well, the next step will be to check the A/C pressures with a set of gauges. I'd bet on a leak, as the truck has quite a bit of age on it and this happened to me when I changed the motor in my '96 Ram 2500.

 

Truck had a motor swap last spring, everything was fine, got a new condenser and complete system recharge and refill over the summer and it has held for months just the same as day 1 until now. I guess anything is possible, but it just seems very very very unlikely. If it was a slow leak, id expect lower performance, not complete lack of, and if it was a major leak, I would expect the lines to not get cold, as there wouldn't be refrigerant.

I suppose I can check anyways though.

 

Lines will still get cold if it lost some refrigerant, but will not necessarily be optimal cooling inside the vehicle - time to get out the gauges to check things. I have found that when dealing with older vehicles, almost anything is possible.