2014 Z71 Tahoe air conditioning question

[Sackett2622]

AC began blowing warm air. Had it serviced, had a leak in a rear line & system recharged. Cold air for a few days, back in for service, mechanic replaced condenser, evaporator, checked for leaks and had him install aftermarket cabin filter receptacle. Cold air for a few days. Back to the shop. New compressor installed and once again had cold air for a few days. I am sort of lost as to what it could be and also out about 1500.00 No confidence to take it back to the same shop. We bought it used in 2019 from Chevy dealership and before we could pick it up upon purchase, they replaced brakes, (front), installed a new stereo, (factory replacement) and charged the ac. The AC worked great for two years after purchase. Any ideas sure would be appreciated at this point.

 

[jared999]

Based on what you have said, that shop never properly diagnosed your issue. It is highly unlikely your compressor, condensor and evap were all bad. Sounds like they were just throwing parts at it. One thing jumps out though - each time you had some work done it worked for a few days right? That is because each time they replace one of those components, they are recharging the system. That tells me you have a leak and they were not able to find it.

First thing you need to do is take it to a different, reputable shop. Tell them you have charged your system a few times and it only stays cold for a few days and that you want a leak test and AC system inspection done. Make sure they use dye. Ask friends, or use Yelp or something but find a shop that knows how to test an AC system.

 

[OR VietVet]

Welcome to the forum.

Like @jared999 said. It sounds like initially the system was fine when you bought it and worked fine for two years. Then you had a low system pressure (leak) problem that parts were being thrown at. Sounds like each time work is done and recharged, the system takes a bit of time for it to leak down and then trigger the low pressure switch and shut the compressor down. When you notice the hot air instead of cold air, do you experience a lack of cooling temp first gradually and then all of a sudden hot air or is it cold and then hot, like a switch was thrown? Slow leaks usually start out as the schrader valves or o-ring seepage and would be surprised if those had not been mentioned so far. With all this work, I would have asked to at least replace the schrader valves while system was empty. Yes, have the system emptied and leave on vacuum for an hour and then shut off and see if holds vacuum and also add dye to system. With rear a/c, there is a possibility of leakage back there as well and may have never been completely looked at looked at. If when the system blows hot and system pressures are good, then you have some other problem but has ANY tech yet mentioned the pressures when you bring it in with the problem? Too many techs are ignoring basics and just immediately throwing parts at the problem and pocketing the money. These techs are called, "parts changers".

 

[Geotrash]

AC began blowing warm air. Had it serviced, had a leak in a rear line & system recharged. Cold air for a few days, back in for service, mechanic replaced condenser, evaporator, checked for leaks and had him install aftermarket cabin filter receptacle. Cold air for a few days. Back to the shop. New compressor installed and once again had cold air for a few days. I am sort of lost as to what it could be and also out about 1500.00 No confidence to take it back to the same shop. We bought it used in 2019 from Chevy dealership and before we could pick it up upon purchase, they replaced brakes, (front), installed a new stereo, (factory replacement) and charged the ac. The AC worked great for two years after purchase. Any ideas sure would be appreciated at this point.

Remove the little caps on the high and low pressure ports and hit them with some soapy water. Hundred bucks says you have a leaking Schrader valve on one or both. $1.99 fix + new r-134a.

 

[CaptainAmerica1]

Remove the little caps on the high and low pressure ports and hit them with some soapy water. Hundred bucks says you have a leaking Schrader valve on one or both. $1.99 fix + new r-134a.

That’s where mine were leaking

 

[swathdiver]

AC began blowing warm air. Had it serviced, had a leak in a rear line & system recharged. Cold air for a few days, back in for service, mechanic replaced condenser, evaporator, checked for leaks and had him install aftermarket cabin filter receptacle. Cold air for a few days. Back to the shop. New compressor installed and once again had cold air for a few days. I am sort of lost as to what it could be and also out about 1500.00 No confidence to take it back to the same shop. We bought it used in 2019 from Chevy dealership and before we could pick it up upon purchase, they replaced brakes, (front), installed a new stereo, (factory replacement) and charged the ac. The AC worked great for two years after purchase. Any ideas sure would be appreciated at this point.

Do you want to find the leak yourself? As for the evaporator, did you see the mechanic pull your dashboard back and replace it?

 

[Sackett2622]

I do not have the equipment to check for AC leaks, if not a fortune would buy whatever is needed at this point! Thanks!

 

[Sackett2622]

Remove the little caps on the high and low pressure ports and hit them with some soapy water. Hundred bucks says you have a leaking Schrader valve on one or both. $1.99 fix + new r-134a.

I will try this tomorrow, thanks a bunch! Will post how it turns out.

 

[OR VietVet]

I will try this tomorrow, thanks a bunch! Will post how it turns out.

Make sure you just check them. There is a special tool that you can buy to tighten them without losing all the refrigerant inside the system. Do not try to unthread them and change them. The system will dump all the refrigerant out, under pressure. Check for the bubbles and tighten ONLY but don't wrench them down too tight. Report back with findings. Look for a rubber o-ring under the cap as well. The bubbles may take a long time to show. No need to run system during the check.

 

[CaptainAmerica1]

I do not have the equipment to check for AC leaks, if not a fortune would buy whatever is needed at this point! Thanks!

All you need is some uv dye and a uv flashlight.