A/C in a 4.6

Topic: A/C in a 4.6 (Read 1573 times) previous topic - next topic

A/C in a 4.6

April 24, 2009, 05:48:50 PM

My air hasn't worked in my car since I bought it. The compressor kicks on, so I figured all it would need was a charge. Went and bought some 134a and and charged it according to the directions that came with it. The air still dosen't work. Blowing very hot. I checked the pressure on the low side (bigger dia. hose) and it was very high, up around 100 psi. I have no knowledge about a/c systems, never worked on one before. Any suggestions?

I bled the pressure down to around 45 psi, and it the air is definitely cooler, but not cold, like it should be. I'm afraid to bleed any more pressure b/c on the gauge I have - (it's the one that comes with the can) it shows that between 30-45 psi is "charged"

A/C in a 4.6

Reply #1 – April 24, 2009, 06:27:29 PM

Now this may be a dumb question, but would the coolant have anything to do with this? I know the cooling system needs to be flushed...

A/C in a 4.6

Reply #2 – April 24, 2009, 06:34:52 PM

Do the rad fans come on?

A/C in a 4.6

Reply #3 – April 24, 2009, 06:53:32 PM

Good question...letting it idle now to see. Is the compressor clutch supposed to run constasntly or kick on and off?

A/C in a 4.6

Reply #4 – April 24, 2009, 07:02:57 PM

After going for a short drive yes the rad fan does come on...

A/C in a 4.6

Reply #5 – April 24, 2009, 08:03:23 PM

The fan should come on with the A/C on even if you don't drive the car. The A/C system relies on the fan to cool the condenser. No fan will result in high pressures and no cooling.

When you observed that pressure reading was the engine running?

A/C in a 4.6

Reply #6 – April 24, 2009, 08:11:52 PM

Quote

When you observed that pressure reading was the engine running?

Nope, it was right after I shut the car off. Even after I bled the air it would still read over 100 psi after the car shut off. So I guess the rad fan not coming on could possibly be the problem, but after I drove it and the fan was on it didn't get any cooler - or would the condenser already be to hot? And again about the compressor clutch, should it constantly run?

A/C in a 4.6

Reply #7 – April 24, 2009, 09:00:56 PM

You should take the readings while the car is running and the A/C is on. With the A/C off the system will stabilize (equal pressure throughout it) and you'll get artificially high readings.

The pressure on the low side should be 24-45 PSI with the A/C on, the ambient temp at 80 degrees, and the engine running at 1500 RPM. I would reckon that since you now have 45 PSI with the engine off your pressure will be way too low with the engine on.

A/C in a 4.6

Reply #8 – April 24, 2009, 09:31:36 PM

Would it be harmful to shoot another can of refrigerant in there to boost the pressure? Then check the readings with the car running.

A/C in a 4.6

Reply #9 – April 24, 2009, 10:41:16 PM

It'd be less harmful to check the readings first, then add refrigerant as needed

A/C in a 4.6

Reply #10 – April 24, 2009, 11:26:02 PM

Yea thats what I meant, I just worded it wrong. Will know more tomorrow.

A/C in a 4.6

Reply #11 – April 26, 2009, 12:08:16 PM

Ok, gonna be working on this some more today, and was wondering how I would know if it needs oiled or not?

A/C in a 4.6

Reply #12 – April 26, 2009, 02:08:50 PM

Unless you replaced something or had a huge leak, chances are it does not need oil. A/C system oil should last the life of the car. When you replace components there is a guidline as to how much oil should be added, but otherwise you shouldn't need to add any.