AC fixed but still not blowing cold air

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Things that have been done recently to the roadmaster-
New: ac drier, hose assembly, condenser, orifice tube.

System was vacuumed out and charged. Oil in. It is leak free

Compressor only has 66k miles on. Doesnt make any wierd noises. Still engages.


After all of this my ac comes out lukecool at best. This cars ac used to be freezing! Any input appreciated.
 
Fan clutch?

My grandparent's Trailblazer had lousy a/c for years, even after recharging the system it wasn't very good. Replaced the fan clutch and
crazy2.gif
it blows ice cold!
 
You can tell a lot by hooking up a set of manifold gauges; most importantly, if the shop cheated you on refrigerant.
 
Garak- the temp adj is working

Wyr- the low pressure line to the drier is getting cold

Chris142- with the gauges on, thr guy at the shop told me the pressure needs to be between 40-50. Was at 40 and he put some more refridgerant in there to be at 45.

The car was on for about an hour today and driven at the ac's highest fan mode and lowet temp. For about 2 minutes i got the tease of it blowing almost as cold as it used to. Then went right back to lukecool. Blend door problem?
 
The basics of refrigeration is temperatures and pressures .

I try to run the evaporator coil at around 35F to avoid freezing the coil .

That , under perfect conditions , with R-134a , to 30.5 psi . So , for me , he has too much refrigerant in your system .

But , if the suction / low pressure line is cool , you should be at least be getting some cool air . If not cold .

So , I am still thinking a problem with a blend door or the control problem .
 
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If the suction line is much colder than the air from the vents, there is a blend door problem.

Charging by pressure, and watching only one gauge at that, is the wrong way to do it. There's a good chance he didn't bother to use a vacuum pump either, which means the refrigerant is contaminated with air and will need to be replaced to get full performance.
 
Also if you're saying it was cold for 2 minutes when you first started the car, then warmed up, that really suggests the heater core is fighting the A/C.
 
Originally Posted By: Merkava_4
You can tell a lot by hooking up a set of manifold gauges; most importantly, if the shop cheated you on refrigerant.
Yup! That's a possibility, been there, chased that problem.
 
Good point about the A/C fighting the heater . Put a water valve in the heater hose & shut it off . Does it have a mechanical , vacuum or electronic gizmo to modulate coolant flow to the heater core ?
 
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Best to buy your own set of gauges / hoses & learn how to use them .

Just because the mechanic hooked up the hoses does not mean he allowed air to enter the system . That is why you purge the equipment .
 
beat me to it.
Originally Posted By: mk378
Also if you're saying it was cold for 2 minutes when you first started the car, then warmed up, that really suggests the heater core is fighting the A/C.
 
Originally Posted By: gallydif
The car was on for about an hour today and driven at the ac's highest fan mode and lowet temp. For about 2 minutes i got the tease of it blowing almost as cold as it used to. Then went right back to lukecool. Blend door problem?

That's certainly worth a check.
 
Originally Posted By: gallydif
Garak- the temp adj is working

Wyr- the low pressure line to the drier is getting cold

Chris142- with the gauges on, thr guy at the shop told me the pressure needs to be between 40-50. Was at 40 and he put some more refridgerant in there to be at 45.

was he using a machine or cans?
 
So I went to my friends friend that has a ac machine. He hooked it up and said the pressure was just fine. He got the Thermometer and tested the vent with the ac blasting. It was coming out lewk cool. The ac machine vacuumed all the refrigerant out- It had .77lbs. The roadmaster takes 1.75lbs of refrigerant. He waid it was strange to have correct pressure but for it to be so low. He put the correct amount in. Blows harder now but still only luke cool.

Says when that happens- reading correct pressure but then refrigerant amount is low like that is the compressor thats bad.
 
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