jkelley

Wanted to trim charge 2010 f150 AC due to suction pressure being at 20 psi. Then, my luck, due to a bad gauge over pressurized the system. Added Freon for a while and pressure not moving. Got concerned so went and got another gauge and of course now pressure at 100 psi with compressor off and not starting. Pressure for current ambient temp should be 35 with compressor running. So I bleed down to 35 (who knows what the original pressure really was but air temperature is what made me think it needed a trim). Now the compressor runs for a period and then turns off. Run time and off time vary from running a minute or 2 then off for some seconds - 10-30. Additionally the 'other' electric fan is turning on and I swear I have never heard it run for as long as I have had truck. Any suggestions??? Please. And yes I have the climate control set at 60 Dee with all windows open. Vent air is good and cold as long as comp is running.

HELP!!!

RLXXI

Depending on ambient temp the pressures will vary, here's a chart to guide you a little.



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jkelley

Thanks. Didn't check discharge pressure but the suction press of 35 psi was based on chart.

Still in need of advice...

RLXXI

You want the system fixed you HAVE to know both sides pressures, plain and simple.
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antony1103

AC systems in general are pretty complicated. First off, you can't really bleed off refrigerant to reach a certain temperature (that is also illegal in the US). The system pressure will always equalize depending on the ambient temperature because it is in a saturated state. You may initially see a lower pressure after bleeding, simply because you vaporized some refrigerant and temporarily threw it out of equilibrium. It would be helpful to know the high side pressure as well to truly diagnose a problem.

In general, if you say the air is cold, the compressor normally cycles based on the system pressure. Not sure if your cycle times are normal without more information on the amount of refrigerant that was charged into the system and the ambient temperature.

If you are concerned, take it back to have the system evacuated and leak checked. If there are no leaks, fill the system with the correct amount of refrigerant. This is typically posted on a sticker under the hood.

jkelley

What about the cooling fan running. Have never heard it run as 'loud' as it does not. And once it starts it doesn't stop (even if I turn off the AC) until truck is turned off. I see a lot of folks posting about the incredible noise they make but no what fixed it. I am thinking pressure switch or something related to the original screwup I made.

antony1103

I'm not too sure about how the fans are programmed, so someone else will have to chime in. I can tell you that the fans on my 2013 also run pretty loud when the AC is on, but they usually slow down about 5 minutes or so after I shut the AC off. I always figured they were working as designed as I don't see any problems other than the increased noise.

jkelley

Well here we go... took to dealer (relatives) and after getting on my *** for not just bringing to them first evaced system and discovered the PVC or TCV whatever was stuck open and popped shut during evac. Changed the test port valves while EMT. Pressed up and now working fine. Said as long as I didn't damage comp seals should be good. Working fine so far. If in need of help and around ZIP 70775 call Bill at Bennett Ford - and be ready NO BS just the straight truth - like it or not - just like I like it!

jkelley

Oh, and $140 to make right...