AC stopped working/surging while driving

[Mark99GT]

My AC suddenly stopped working/compressor would not turn on and I had a pretty noticeable engine surge. I replaced the low pressure switch and the compressor kicks on, no surging, and I have nice cold air again. Is this indicative of another potential problem or just that the switch failed? Best $20 fix ever, hoping there's nothing else to worry about...

I hooked up a recharge can to the LP port and had good pressure per the gauge, so it didn't need charging. There was also a green substance at the LP port when I took the cap off. AC dye I'm assuming?

 

[MG0h3]

Affirm. Oil has dye in it.

You can rent gauges at Autozone or most retail parts stores.

AC was one of the things I’d never tackled before and decided to learn on my shitbox focus.

Found the front seal on the compressor leaking so new compressor, bunch of orings, dryer/accumulator and orifice.

Used their vacuum pump and gauges to ensure I was sealed up, sucked the refrigerant in and gtg.

The gauge on those cans is sort of an indicator but it’s nice seeing both high and low side, especially at cruise rpm.


Sent from my iPhone using svtperformance.com

 

[Mark99GT]

Affirm. Oil has dye in it.

You can rent gauges at Autozone or most retail parts stores.

AC was one of the things I’d never tackled before and decided to learn on my shitbox focus.

Found the front seal on the compressor leaking so new compressor, bunch of orings, dryer/accumulator and orifice.

Used their vacuum pump and gauges to ensure I was sealed up, sucked the refrigerant in and gtg.

The gauge on those cans is sort of an indicator but it’s nice seeing both high and low side, especially at cruise rpm.


Sent from my iPhone using svtperformance.com

Thanks for the reply. You think it's worth looking into further with actual gauges (I agree with you about the accuracy on recharge can) or just leave it as is? They dye leads me to believe it was tested recently as none of my other cars have dye on the LP port--I got the car from a Ford dealer.

On a side note:. Why would the bad LP switch cause an engine surge? Just curious, not sure how the two are related.

 

[Mark99GT]

So now it's all of a sudden hanging around 1800rpm and slooooooowly idling down to nowmal 700rpm idle when driving and shifting into neutral. AC compressor related? Also started making a weird grinding-like noise when parked and idling with AC off......wtf....bad pulley?

 

[MG0h3]

I suspect you have something else going on.

Low pressure switch is exactly what it’s called; should not cause the other problems that you are describing.

Once my AC system was essentially empty, the compressor just cycled on and off continuously as the LP switch kicked it off.


Sent from my iPhone using svtperformance.com

 

[shurur]

A hanging idle can be leak in vac lines (I think).

You can spray starter fluid around the lines to find it.
The car is at that age where this stuff happens.

As these cars age, you can get multiple issues...seemingly appearing all at once.

Load the torque app on your phone..get a obd2 BT BAFX dongle on Amazon and read for codes.

As for AC..Chris Fixx on youtube has a great video on how to use the gauges and vac unit...or as often as you need to do the AC..it might be easier to take it to an AC guy..it depends on how many cars you have in your fleet.