AC leak SOLVED!! Also Need your opinion on my mechanic

[Iluvteak]

2003 Tahoe

First off, thanks for all the threads on here. Very helpful when dealing with my AC leaks. I wanted to give you my solution as many times a 'final post' is not added to the threads.

I'm driving thru Texas on way to FL. My AC was blowing warm air so I added 3 - 12 oz cans but couldn't get it over 25 psi on the low side. No obvious leaks. I was trying to reach 35-45 psi. I tried 2 gauges but they were the cheapies from autozone.

Finally added some r134a with Super Seal and let it sit overnight. Added another roughly 30 oz of r134a but same problem. Couldn't get it over 25 psi. I decided it was time for the shop to have a look. Also looked like the low side port was leaking as the autozone gauge was so difficult to get on it damaged it.

The shop evac'd it and changed out ports low and hi. Added 2.7 lbs of r134a and said it was fixed. 1 hour of driving later it is blowing steam out of middle vent. Ughhhh. And not cooling very well. Still reading 25 psi too. I call the shop and they say that's normal. What?? I demand that they check pressure again with their gauges! They say PSI means nothing.

After humoring me and guilting me I finally ask them how much freon they are putting in. It better be 2.7 lbs I say. Suddenly the service mgr leaves on an errand. Another tech comes in and says they didn't fill it correctly based on front and rear AC. Used the front AC specs. Oops. :happy160:

WOW. So the lesson is don't trust these guys. Not sure if it was a real mistake. Or were they setting me up for the 'your compressor is shot' speech?? Then I mentioned the 2.7 lbs and they gave up. I will never know much it seems a bit fishy to me.

Hope this helps. Opinions on the shop??

 

[MO Viet Vet]

Use another qualified shop. Too much drama and misinformation at the other one. The steam out of center vent makes no sense. That to me indicates a leaking heater core or water back up inside the housing under dash from a clogged evaporator drain tube. Have next shop check for that and also pressure test the cooling system and evacuate the a/c system and add correct amount of R134A. Then monitor gauges. Because you may indeed have a leak in a/c system have them evacuate at least 30 minutes. When it is evacuating any moisture that could have gotten in to the system from the leak will turn from a liquid to a gas and the evacuation pump will pull it out. Make sure the condenser is not full of crap either. Need good air flow. Restriction there can cause too high gauge pressure readings.

 

[Iluvteak]

Thx. I'll chk the evaporator for bugs. It's a bit hard to inspect, just behind the radiator right?

Shop claimed they evac'd it for 15 minutes so hope I'm good on leaks. FYI they charged $240 for the job. Evac, change 2 ports, fill and add 1 lb of freon. Seemed high but after all that it's blowing cold front and back AC.

 

[MO Viet Vet]

Evacuating system does not fix leaks. Replacing valves at ports could have fixed the only leak or there are others. Condenser is in front of the radiator. Sometimes have to remove grill for access or remove the attachments at top of radiator and try to lean back to get to the condenser but may only expose the back and no front. I have a special tool I built that is a long wand with a 60 degree bend at the end that I can reach in between front of radiator and back of condenser and use compressed air to blow debris out from the back. If you do that from front it typically pushes the debris in deeper into the condenser and that doesn't fix anything. While in there if you see any fins on the condenser laid over then bend them back straight for more air flow. I have a condenser comb for this.

 

[Iluvteak]

Great idea, I'll try to clean the evap. Thx Raider.

 

[remauto1187]

Great idea, I'll try to clean the evap. Thx Raider.

Condenser is in front of your radiator. (heat is exchanged from the refrigerant to the atmosphere here). Evaporator is under the dash in the ductwork and this is where humidity(with heat) evaporates once it reaches the cold evaporator and the heat is absorbed by the refrigerant and carried off to the condenser. More things happen in between but this is the dumbed down version.

Wanna learn more? Checkout the compressor and how it works, orifice tube(valve), receiver/drier, difference between hi and low side and the state of the refrigerant in these areas of the system, hi/low pressure switches and the clutch for the compressor. :happy160:

There is no real difference between your refrigerator/freezer, deep freezer, window ac unit, central air system and your auto ac system other than refrigerant type used and capacity of cooling. They all do the same thing and they are all dehumidifiers.
You can use fire and many other types of heat sources to warm/heat air to make hot air but you cant cool air to make cold air. Cold air is warm/hot hair with the HEAT removed from it which leaves...cold air.