Had previous issues with truck overheating....fixed by replacing the condenser fan (it kept blowing the 40 amp fuse, eventually ceased altogether). The fan now works fine and turns on when A/C turned on. The A/C had not been blowing cold for a couple of years. Not a daily driver - so lived with it.

I just recharged with kit from Advance Auto. I followed the kit directions taking into account the outside ambient temperature. After bringing low side pressure up to about 35 lbs, the compressor engaged, but still no cold air. Compressor also does not cycle. Once on, it stays on.

The blower fan inside the truck works fine. Temperature gauges seem to be working because it will heat.

Ideas?

 

Take it to a shop to have the system evac'd and recharged. You likely have a leak that needs to be addressed.

 

It did not lose any pressure, if there was a leak, wouldn't that happen?

 

Without a pair of gauges you are guessing. Could also have bad drier. Evac and recharge is best plan.

 

Done my share of A/C work.
You will get the most efficient operating system by doing an Evac.

BUT
If you kept pressure in there - some pressure say 5 lbs or so--
Then you are probably OK.

If you got down to NO pressure, then you need an evac as moisture may have entered plus air.

OK, so if you did NOT open the system and you had pressure.

We take into consideration:

1) You are on LO on the front panel
2) Your compressor is turning - and it keeps spinning with out turning on, off, on, off

Note the LOW side fill plug you used.
Note where that hose goes to aluminum on the compressor.
Look for condensation or feel it to figure out how cold it is.

If it is not cold and you have 35 pounds of pressure when the system is running - you may be too low on freon.

On the other hand --
If the compressor is going on and off and cycling when you re on LO on the front panel temp control then you may have OVERCHARGED the system.

An overcharge will exhibit by a cycling compressor.

----
If you are not overcharged and the compressor is running all the time - then fell the low side compressor connection - is it cold or just warm?

Feel the high side connection *carefully* it may be hot or burning hot.
Highside is usually HOT before the low side even gets cold.

If the low side is just a tad cold, shoot in 10 seconds of R134 and no more of that.
Bottle face down so that liquid gets in.

Feel the LOW side connection for cold.

If a bit colder then wait a bit and feel again.

Should be at least 50 degrees and air should be 50 degrees from vents.

If it got a little cold, then shoot in 10 more seconds of liquid - or maybe even just 5 seconds.

There is A DELICATE balance of too little,
just enough - for the best cooling and
to much R134 which will decrease cooling again.


Charge too little: warm (under charged)
Add 10 seconds - colder (under charged)
add 10 seconds colder (probably perfect charge)
add 10 seconds - no change (maybe a tad over charged_
add 10 seconds - a bit warmer (over charged)
add 10 seconds - warmer and compressor cycling (over charge)

Best,
J

 

Stop messing with the AC and take it to a pro.

 

go have a vacuum pulled on the system all you did was add refrigerant to a system that had air in it.
those DYI kits are fine if you need to add an oz or two to an already operating system, otherwise your just throwing money away.
Oh and dont be surprised when they come back and say they could pull a vacuum because you have a leak in the system, the refrigerant went somewhere.