A/C Not Cooling

Gail Technician North Carolina Posted   Latest   Edited  
Updated
HVAC
2014 Chevrolet Express 3500 6.0L (G L96) 6-spd (6L90)
Poor Cooling

Vehicle has poor cooling at vents. Approximately 70* on MAX air setting. 53 Low side, 225ish high side. Lines at accumulator were warm to rear air. Evac & recharge revealed system was about 1/2 lb low. (evac'd 2.83/charged to 3.11) No change in performance. Vehicle had new parts everywhere from previous repair attempts at another shop. "New" compressor, accumulator, condenser, evaporator, radiator, water pump. I had previous experience with this companies vehicles where A/C had been repaired and the tech did NOT install an orifice tube. Removed orifice and found old style part

My previous experience used a much different part. Installed a "new" orifice. Still not cooling and LS reading still too high (55ish). When RPM raised LS drops to 43 but HS goes 350+. Fan clutch is operating normally. I called a plugged condenser. Replaced. No change. It IS cooling, didn't get a temp cause it wasn't close to good, but HS is still too high. Have pictures on phone. I'm stumped. Rear air is colder than front but not working to potential.

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Gail Technician
North Carolina
Gail Update
 

Gauge readings are at idle fairly early in repair attempt. I've actually made it worse as far as pressures go. Front cooling has improved but still not even close to good. Our ambient temps are 95+ with high humidity. Tried reducing charge level with no improvement.

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Hector Owner/Technician
Florida
Hector Default
 

have seen similar issue with same symptoms I also called a bad condenser and replaced with aftermarket after days of pulling my hair out the fix was an original condenser, hope that helps

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Albin Diagnostician
Washington
Albin Default
 

Your high side of 350 + Psi says your condenser is running too hot. Is the problem an air flow problem, or the condenser not removing the heat from the refrigerant? Condenser inlet and outlet temps would be helpful.

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Gail Technician
North Carolina
Gail Default
 

I'll see if vehicle is still at the shop in the morning. I need to buy a thermal imager. Have an old school heat gun though.

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Samuel Technician
New Jersey
Samuel Default
 

Also, even though he has seen the fan clutch moving, it does not mean it is flowing the amount of air it needs to....curious

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Haris Technical Support Specialist
New York
Haris Default
   

There is a lot of metal debris on the orifice tube you removed. Makes me wonder why all the previously mentioned components were replaced. You may have a contamination concern thats affecting your AC operation. I also see that you are experiencing extremely high ambient temps and humidity. On Express vans with rear A/C, 95F/100% temp/humidity, 51-73 LS/ 219-270 HS with a vent temperature at…

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Rick Technical Support Specialist
Missouri
Rick Default
 

Make sure the temp door is fully closing. They will make a thud noise from time to time when reaching their full stop. I have not had one fail yet but that is what goes through my mind every time I here the thud.

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Gail Technician
North Carolina
Gail Default
   

I suspect it has an issue with temp blend door. It's much cooler today so pressures are acceptable. 40ish/200. Still no cooling enough to suit me. Pinched off heater hose and saw almost immediate 10 degree drop. Condenser temps 109/127 best I could get. I'm pulling the evaporator to look in the box. They didn't get it sealed up anyway so needs attention. Air blowing out at bottom line. They left…

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Gail Technician
North Carolina
Gail Default
   

Horse pucky. Blend door stops about 1" short of being closed. Dorman strikes again.

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Gail Technician
North Carolina
Gail Update
 

They got me another Dorman. Same. Motor isn't pulling tight enough to make it hard to get off. Can move door by hand completely free. Want dealer part. Tomorrow.

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Pam Owner/Technician
Florida
Pam Default
   

930a EDT: There’s a mired of things that must be addressed before going forward, so we can help you, help your customer: - Before going further, check the engine cooling system. Especially air flow and radiator performance (Plugged, etc.). This can give you a false positive - the root of the evil in this system. (Definitely get a thermal imager! I’ve had one for years. Love it! Use it for…

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Gail Technician
North Carolina
Gail Default
 

I was unaware of the door being pulled open at KOEO. I'll see what happens with it running. The pressures were fine today. I suspect an oil overcharge was creating my high side issues. But inlet temp at evaporator was 66 at best. I want to see 40 ish. Don't remember outlet temp. Condenser temps were 109/127 at idle. I evacuated and recharged at least 5 times yesterday. Got oil out every time…

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Gail Technician
North Carolina
Gail Default
 

Can anyone explain the correct actuator "calibration" for these? I've seen some stuff about removing fuses and opening/closing doors, etc.

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Nelson Diagnostician
North Carolina
Nelson Default
 

I agree and suspect that the system has an excessive oil charge which is affecting heat transfer. Too many shops don't know about "oil balancing" the AC system when replacing failed components. They will just slap on a compressor with an 8 oz oil charge inside it and call it "done" and them wonder why it is not cooling properly. I typically suspect an excess oil charge when I see oil draining…

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Gail Technician
North Carolina
Gail Default
 

I have the evaporator loose so I'll remove it and dump the oil. This is all great info. I really appreciate every comment. I always assumed the oil would end up in the accumulator.

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Samuel Technician
New Jersey
Samuel Default
 

Exactly....I would say heck with the blend door until the manifold readings are resolved.

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Gail Technician
North Carolina
Gail Default
 

It was a stumper. Shop decided to punt it to dealer. I'm really depressed...i hate to give up. I still suspect the fan clutch, even though "new", wasn't pulling enough air. The condenser inlet/outlet temps were less than 20 degrees different. What difference is appropriate on something like this?

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Nelson Diagnostician
North Carolina
Nelson Default
 

As a rule of thumb, I like to see at least 25 degrees difference from inlet/outlet measured on the condenser using thermocouples. Our shop has been using thermocouples for a few years now and we have been able to identify heat transfer problems that others have missed. If you are using an IR noncontact thermometer for temperature measurements, that will not produce the accuracy you need. Two…

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Samuel Technician
New Jersey
Samuel Default
 

Nelson, googling this now!

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Samuel Technician
New Jersey
Samuel Default
 

Gail, suck that they shipped it off....the misconception that the "dealer can do it" to me is bogus! They are techs like the rest of us and sometimes are limited on abilities and equipment. I know I have tools and experiences they may have never seen, simply because I work on everything. No slam on a good dealer tech. Simply no reason to think they will have the answer any more quickly than you.

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Gail Technician
North Carolina
Gail Update
 

i guess the customer wasn't too mad. They brought us a 2016. On this one the temp door actuator was bad. But we learned something. After some digging found we were using the wrong actuator. This one works. I didn't use the "transmission" as one of the bolts is really hard to access and I had it off the 2014 with nearly 100k more miles. It wasn't broken or worn so didn't change it. 53 ish…

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Gail Technician
North Carolina
Gail Update
 

Groundhog day continues. Flushed evaporator and condenser to remove excess oil. Replaced accumulator and installed normal orifice tube. 53 degrees @ idle, 47.5 at cruise. But that's with temp door disabled and blocked closed for cooling. Quit moaning when shut off.

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Nelson Diagnostician
North Carolina
Nelson Default
 

Have you made temperature measurements at the inlet/outlet lines from the evaporator? For the best accuracy, I use thermocouples. The results you are looking for ideally is no more that 5 degrees difference. This test determines if you have an adequate refrigerate charge in the system. I know you have stated that you have charged the system several times, but also you mentioned several…

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Gail Technician
North Carolina
Gail Default
 

Flushing and changing accumulator and orifice tube fixed it. But temp door is disabled. THAT is what has me puzzled. The actuator is at Max travel. Arm on door has to move another 1/4" to close door (cold position).

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Caleb Technician
Indiana
Caleb Default
 

Are you using the Dorman actuator shown in the pic or a Dorman actuator?? If so, that is the problem. Get an OE temp door actuator and I bet it moves full range then.

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