Any knowledgable A/C gurus here?

[one eyed willy]

Wife's 08 V6.

Few weeks ago I noticed it was blowing cold on and off.....now it's just blowing hot.

Blower motor and controls are all good. I bought some freaon to add to the system but the gauge says its already full, so it's not a leak.

The compressor clutch kicks on and off, if I disconnect the high pressure switch it stays on. So I'm guessing it is building pressure and that's what is causing it to kick on and off?

All fuses are good, I swapped around relays so they are good as well.

What else could it be?

Click the pic below to watch what the compressor kick on and off.

 

[Paps]

Bad evaporator?

 

[Sprayin Blue 3V]

You really need to get a manifold gauge set on the system to actually see what is going on. People can guess all they want but without testing the system, a guess is all it is.

 

[one eyed willy]

I know nothing of a/c, what would it tell me. The gauge I used was for filling freon on the low pressure side and it was in the red as for having too much pressure.

I don't know how the a/c system works, but to me it looks like the compressor and clutch are working, building pressure...and then the high pressure switch turns the compressor back off.

I open to try whatever, just not sure how to diagnose or the next step?

 

[white05gt]

You really need to get a manifold gauge set on the system to actually see what is going on. People can guess all they want but without testing the system, a guess is all it is.

He's right but I'm guessing it's a little low on r134. Usually the compressor will cycle when the system is low, the clutch will engage until the low pressure side gets low enough that the clutch disengages. Once the pressure starts to equalize, the clutch will engage again. It's easily checked with a set of gauges, the clutch will disengage around 20 psi on the low side when the system is low on r134

 

[saleen07gt]

Get some gauges on the system. Low side should read about 30-35 psi, high side should read at least 150 at idle. Before you even start the car with the gauges on your static pressure should read about 10 psi higher than the temp outside. All of these figures will vary with temp and humidity but a good starting point for ya.

 

[86GT351]

I know nothing of a/c, what would it tell me. The gauge I used was for filling freon on the low pressure side and it was in the red as for having too much pressure.

I don't know how the a/c system works, but to me it looks like the compressor and clutch are working, building pressure...and then the high pressure switch turns the compressor back off.

I open to try whatever, just not sure how to diagnose or the next step?

The Fill can gauge is not going to tell a true story Paul. Need to get a set of gauges or have it checked to see what both pressures are.

With the system properly filled pressures should be approximately 200 on the High Side and 30-35 on the low side.

Here is a basic diagram of how an Auto AC system works based on Freon. Our system has a Fxed Orifice Tube instead of the Expansion Valve and an Accumulator instead of a Receiver Drier.

If the pressure is in the Red on the Fill Gauge or Low Side there might be a blockage in the system. When you drive and there is obvious cool air coming accross the COndenser doe it get cooler?

 

[one eyed willy]

What gauges would I need, only ones I saw at the store were used for filling? With hoses that went to the tank. I'm guessing I could find some videos on YouTube on how to use the gauges?

 

[86GT351]

Something just like these Paul

 

[white05gt]

They are simple to use, the blue one (low side) will only fit on the low side and the red one (high side) will only fit on the high side so there is no way to mix them up. THe yellow is used for filling and is just left hooked up on the gauge manifold unless hooked to a bottle for charging the system

 

[86GT351]

They are simple to use, the blue one (low side) will only fit on the low side and the red one (high side) will only fit on the high side so there is no way to mix them up. THe yellow is used for filling and is just left hooked up on the gauge manifold unless hooked to a bottle for charging the system

Correct. Just make sure that the knobs are both closed. The hose ends snap on to the fittings. Once they snap on go ahead and turn the knob where you connected to the right to open the valve. You will see a pressure reading. Start the car on Max High and let it run for a minute or 2 to see what readings you have. If you do this tomorrow and need, call me I will help you out over the phone!

 

[one eyed willy]

Update:

Guess I wasn't sure what I was looking at today when I did it. Just went out and checked it and it was only at 12psi. So I started adding the freon and the compressor stopped cycling back and forth like it was, the pressure came up got stable. Using my temp gun down one of the a/c vents....it came down to 16 degrees...

Now I'm just curious where the leak is at? The stuff I used is suppose to stop leaks so I guess we will see..

Thanx for the help!

I do believe I will pick up a set of gauges anyway for future needs...I have to replace the entire condenser on my GT....sigh.....it's got a huge hole in it,lol

 

[white05gt]

YOu never want to use any kind of stop leak in an a/c system.

 

[TurboX]

YOu never want to use any kind of stop leak in an a/c system.

Just curious, why ?

 

[white05gt]

It can plug up the system and some shops won't touch the system if they know it has a stop leak product in it. It's basically like using stop leak in a radiator, it will stop the leak but can plug up the heater core in the process.

 

[one eyed willy]

Well what's done is done, hopefully all will be ok.

 

[86GT351]

Varied thoughts on the stop leak. I also know shops that won't use it. As for the Stuff you addeed. Did it have dye in it also?

 

[one eyed willy]

Don't know, never actually saw it, went right in!

 

[86GT351]

Don't know, never actually saw it, went right in!

It will say on the can if it does.

 

[one eyed willy]

No mention of dye