Cant get my A/C cold!!

[slow_90firebird]

Hey guys ive been struggleing with this issue for the last few days now and it getting hot and id really like to have it working for this summer...

So, since I bought the truck the a/c has been kinda cool but not cold at all. Last week, I picked up guages and checked out my a/c. First I noticed that the compressor was cycling on and off every 10 seconds or so. Checked the pressures and low side would drop down to 10psi and then level at about 20. High would steadily climb to about 150psi.

So first I put in one can of freon, and it helped such a small amount its not even funny. Got up to 15/160. Still cycling. So I got a 2nd can of freon and put that in too! Cant need any more than that now. Now my low only drops to 20-22 and then levels out between 25, sometimes 30. High side was climbing real high though like 250. Compressor still cycling on and off, so i tried blocking the condensor for a little bit. I wish i had my guages on at that time but it must have gotten super high and I found out the safety blowoff works ha ha. But the compressor stayed on.

Unblocked the conendser and high side went back down but started cycling again. Hit the condenser with cold water from the hose and it got the highside to 160psi again, but still cant get the low side to 30 or more where I want it.

All of this I have done and air is not significantly cooler than before. I want it cold. My vents only get 10* colder than ambient, but it does dehumidify very well. But everybody says that R12 is supposed to blow ice cold, and im in $50 for the 2 cans of freon now and no gain.

any other ideas?

thanks

[diesel freak01]

sounds possible that your orfice tube is plugged or something of the nature

[PToombs]

Is the evaporator clean? These trucks are known for crap blowing in and plugging the front of the evap. Most guys carefully cut a hole in the front of the box and then glue it back after cleaning. I saw pics someplace, either here or TDR, can't remember which though.

[slow_90firebird]

Yeah I im not even sure where the evaporator is located in there lol. I was actually gonna try pulling out the bower motor and see if I could get in through that hole.

Well today was pretty hot out and I used what little a/c I have. It was 99* out and about 95* on the ride home. I used a thermometer to measure the temp at the vents right when I got home from a 45min ride in traffic. It was 65* so I had a 30* difference. But then again one of the cars they recharged at work today got 42* right in the 100* weather and that was R134a.

I also found out that when it is real hot out and the motor is hot, the compressor stops cycling. It just stays on like I want it to. But spraying cold water on the condenser makes it cycle again and actually made the vent temps 5* warmer.

Oh and I took a reading on the pressures later tonight when the compressor was staying on. Ambient temp about 80* out. It was holding steady at 22 on the low side and 250 on the high side.

[ellis93]

Exp. Vavles are what our trucks use to turn the liquid to gas. Yours may be stuck and not doing its job. The proper pressure will depend on outside temp. You need to have 190 to 200 pounds on the high and you need a good fan clutch to pull air through the condensor. 134a will work in our trucks fine just use 30% less of it than 12. It expands at a higher rate.

[slow_90firebird]

Well yesterday I got time to mess with it so I took the blower motor out and blew air through the evap core and leaves came out the intake vent onto the floor. So I decided I needed to cut a hole and find out what was in there, so I made one that is removable. But it was like half clogged with leaves and they were starting to compost and rot in there from the a/c water ha ha. Well I cleaned it out best I could, and get more air from the vents.

But the a/c seemed to blow less cold than before now. I didnt measure the temp but I will keep an update the next hottest day with the vent temp and the new pressures.