A/C Help - Not getting cold

[Ryan Schaecher]

It used to be that the A/C would be cold by the time we'd be out of the driveway in the ST (my 1996 Taurus still does). Now, 10 minutes later it starts getting cool. It takes 20+ minutes to get comfy (nad you need to keep the setting on MAX/Full Blast the whole time).



Plenty of refrigerant, on the cusp of too much.



Any thing that I can check or should I just take the sucker in to get looked at?

 

[Scott Tanner]

Too much refrigerant is just as bad as not enough... I would check all of you vacuum lines, as if the vacuum fails, the system defaults to heat.. BTDT...

 

[scott degroot]

How do you know that there is enough refrigerant in the system?

 

[Wes Davis]

Yup your reading of too much refrigerant is probably an indication of high pressure caused by a blockage. Clogged orifice tube or something of the like.

 

[Scott Tanner]

auto a/c systems are known as critical charge systems, meaning that you need the exact amount in it. Too much will back refrigerant up into the condenser, decreasing the area needed to reject heat, and driving the discharge pressure up. Consult a service manual or proffessional for the proper suctin and discharge pressures for that vehicle. You may want to get it leaked check, because you may have a leak.. I would check the vacuum hoses as in the post above....

 

[Gavin Allan]

Evacuate the system to a minimum of 400 microns and weigh in the correct charge of refrigerant.

 

[EddieS'04]

Ryan, I dont know about you but the gulf coast of texas temps, have played havoc with the best systems, this summer.

 

[Boodrodon Dykes]

You aint kidding Eddie, its been a hot one this year!.



Im with L1tech, you sure you have enough? and agree with others, too much is just as bad, can keep your compressor from working.







Boodro

 

[Ryan Schaecher]

For the most part it's been mild and enjoyable in Arkansas this year (it's that da,m global warming thing ya know).



I say that it's on the verge of overfill because of the gauge on a can of refrigerant that I picked up 3 years ago at Wally World...



I'll probably take it in next week to a local shop.



I know that the relay hasn't been cycling like it used to. Maybe it's come loose or gone bad. Guess I should check that first... I am an Electrical Engineer... I think I change a relay if need be.

 

[scott degroot]

The problem with going strictly by pressure readings when when diagnosing ac is that you are ASSUMING that the system has no mechanical problems, also unless you know the pressure to temperature relationship of R134a you have no idea what pressures to look for and when to be looking for them. Used to be years ago that automotive ac systems held alot of refrigerant so you could get by with uisng the pressure method...or guessing as I like to call it, but with todays systems on average using only about 28 ounces proper system charge is very crucial in insuring proper ac operation and after 20+ years of doing ac work I can't tell you the pressure difference between 28 ounces and 24 ounces...theres just to many variables involved

 

[Gavin Allan]

Your system could also be full of noncondensibles too.