97 F150 A/C Not blowing cold.

[sawillia]

I got this truck out of Texas off Ebay so i don't know much about it's history.... The air wasn't blowing cold so I pumped in a Can of R134a and also a can of the Oil.... It blew cold for just a bit and now it's warm again. I got another can thinking Ihad a leak but the system doesn't seem to want to take it... Any ideas? Am i doing something wrong? I was thinking the compressor but i'm really only shooting at a guess. Thanks in advance gentlemen... Saw

[svt_sc_f150]

A can of oil is too much. Now you probably have too much oil and not enough freon. But you should still have it checked, the pressures need to be checked.

[Quintin]

The system needs to be drained, swept, and recharged and leak tested with a UV light. If you hadn't had added that extra can of oil, we probably could have worked with something. But now chances are, like svt_sc sez, you've got an overcharge of oil. However, in the meantime to try to get a general idea of if you have a leak, you could head to Wal-Mart or AutopepboysAdvanceZone and buy a UV pen light and start looking for leaks.

[sawillia]

I've got a black light I'll start looking around...

I'll also pull PSI readings...

Now how can I drain the system? Can I do that myself?

[svt_sc_f150]

The most common place on these trucks for leaks is the compressor. They leak out of the front seal. Take off the 8mm bolt that holds the clutch disc to the compressor, look inside where the shaft is, chances are that it will be wet. Other places to look are where the manifold line bolts to the compressor, also check the connections of the whole system. You can usually see oily dirt around the connections if they are leaking. To drain it, you should remove the compressor, remove the accumulator, drain both as best as you can. Do not use cleaners inside the compressor or the accumulator. The evaporator has two connections, the accumulator is one of them and the high side is the other one(smaller diameter tube). There is an orifice tube at that connection, remove the orifice tube with some needle nose pliers. You should replace that as well. Using some shop air blow out the evaporator. Don't forget to put some rags over the end of the tube where the air and oil will be coming out. Do the same thing to the condensor. After the compressor is drained add 4oz of PAG oil to the hole where the bigger tube goes. Then add 2oz to the accumulator. Put it all back together, evacuate it for about 45 min., just to be safe. Let it sit with a vaccum for about 15 min. If it looses vaccum, you have a leak, if not then charge it with the balance of oil that is needed. Check the sticker that is under the hood. Then charge it with the freon. That should just about do it. Some one chime in if I missed something.

[sawillia]

Ok here is what I've done. O by the way... thanks in advance for any help I can get. I have to admit I'm an AC newbie...

I connected the pressure gauge to

high side was 20 or 25... (engine off)
Low side was the same (engine off)

I turned the truck on and tested both again... And I noticed the compressor wasn't engaging at all.

I took off the low pressure sensor and jump across the two wires. It cycled the compressor and the readings are as follows

Hi 125-130
Low side was started out at 2 and went up to maybe 40.

If I let the jumper go the compressor cut off...

The connector on top of the accumulator was loose enough for me ot spin it around...

What's next?



Earlier I did notice the thing cycling and now the compressor doens't seem to come on unless jumped?

I'm a bit confused

Thanks

Edit...

I added another can of Frigerant with the low pressure switch jumped... seems to be cooling now... Seems like I'm into the leak detection business

Thanks
Saw