04 avalanche blows air, but its not cold

[Arussell776]

Hey Folks, I'm certain there is a thread for this, but I couldn't find it in my 5 minute search. So here I am.

04 Avalanche that blows air, but it's not cold.

It's full of refrigerant, has a new blend door actuator and had a new control module installed in 2018( by the original owner).

I live in the south and would like AC specifically so my toddler can ride around with me without overheating. And I can take it on road trips again.

I don't necessarily have the money saved to take it to a mechanic for them to vacuumall the refrigerant out and do a diagnostic and then Charge me to refill it.

Where should I start?

 

[EXT4ME]

I also live in the South and I have a 2003 Avalanche and a 2004 EXT.

The one thing I have done to both of my trucks that has helped with both the a/c performance as well as low speed and idle engine temperatures is to replace the old, worn out OEM standard duty engine fan clutch.

I found long ago that the OEM standard duty fan clutches were designed mainly to be QUIET and they do not pull as much air through the a/c condenser and engine coolant radiator as a SEVERE DUTY fan clutch.

Add to that the fact that your existing fan clutch, if it is the original one, is very likely worn out and it pulls even less air than a brand new OEM standard duty fan clutch.

When I first bought each of these trucks used, both of them suffered from poor a/c performance, especially at idle and during low speed operations.

They both also suffered from the engine coolant temperature rising in stop and go traffic in the heat of summer or during extending idling.

Installing new, direct replacement OEM standard duty fan clutches only helped to a small degree.

Now, both trucks have a Hayden Automotive 2786 Premium Fan Clutch installed.

The a/c is now cold at extended idle and during low speed operations and the engine coolant remains rock solid at all times.

Now understand, the SEVERE DUTY fan clutch will produce more noise than the OEM fan clutch, but that is because it is pulling a lot more air through the system.

I find the severe duty fan clutch to make more noise at first cold start up until the engine reaches normal operating temperature.

Then the fan gets much quieter.

Until, the engine is placed in a high heat load situation like extended low speed operation or idling during the high heat of summer.

At that point, you are certainly going to hear the engine cooling fan roar quite a bit more.

But, that sound you hear is the severe duty fan clutch doing it's job.

Pulling a lot more air.

I am totally OK with that as I sit in stalled traffic up on the highway for an extended period of time and my engine stays cool and my a/c stays cold.

I have to wonder if all of the other drivers with me in that traffic jam can say the same.

And by the way, a conversion from a fan clutch to an electric fan system is also a viable option, but you will need to understand everything you will need to buy and do before taking on that project.

Or, you can just spend the $50 for the severe duty fan clutch and see if that solves your problem.

 

[Arussell776]

Thanks for the tip! I'll see if I can try that soon and report back!

 

[ToyHauler13]

Just thinking about what I would verify first. Seems obvious but it wasn't mentioned. Have you visually confirmed that the AC compressor clutch has engaged and the compressor is running?

 

[EXT4ME]

One other thought to keep in your back pocket:

When checking the refrigerant pressures in your HVAC system, the pressures are highly dependent upon the ambient air temperature.

If the a/c condenser is heat soaked (due to low air flow across the condenser caused by many things such as a worn out fan clutch) your pressure readings may not be optimal and that could result in an improper refrigerant charge and possibly even a compressor kicking off due to the high pressure switch tripping, even if the refrigerant charge is correct.

In other words, if it is hot outside, and your worn out fan clutch isn't pulling very much air through the condenser, especially at idle, your compressor may cycle needlessly and it would be very hard to make sure you have the proper amount of refrigerant in the system.

If it were me, I would confirm good airflow and go from there.

That might be all you need.

One very down and dirty test is, with the engine off, grab a fan blade and try to give it a spin.

If it spins more than 1/8 to 1/2 turn and has little or no resistance, the fan clutch is most likely done for and needs to be replaced.

It should not easily spin a couple of turns, for sure.

 

[Arussell776]

Just thinking about what I would verify first. Seems obvious but it wasn't mentioned. Have you visually confirmed that the AC compressor clutch has engaged and the compressor is running?

I can see the clutch and it is moving the belt. I'm glad you said something!

 

[Arussell776]

One other thought to keep in your back pocket:

When checking the refrigerant pressures in your HVAC system, the pressures are highly dependent upon the ambient air temperature.

If the a/c condenser is heat soaked (due to low air flow across the condenser caused by many things such as a worn out fan clutch) your pressure readings may not be optimal and that could result in an improper refrigerant charge and possibly even a compressor kicking off due to the high pressure switch tripping, even if the refrigerant charge is correct.

In other words, if it is hot outside, and your worn out fan clutch isn't pulling very much air through the condenser, especially at idle, your compressor may cycle needlessly and it would be very hard to make sure you have the proper amount of refrigerant in the system.

If it were me, I would confirm good airflow and go from there.

That might be all you need.

One very down and dirty test is, with the engine off, grab a fan blade and try to give it a spin.

If it spins more than 1/8 to 1/2 turn and has little or no resistance, the fan clutch is most likely done for and needs to be replaced.

It should not easily spin a couple of turns, for sure.

As far as the refrigerant res

Just thinking about what I would verify first. Seems obvious but it wasn't mentioned. Have you visually confirmed that the AC compressor clutch has engaged and the compressor is running?

I stand corrected. I could see the belt turning the compressor pulley, but not the clutch kicking on, upon further inspection the clutch isn't starting.

 

[Arussell776]

One other thought to keep in your back pocket:

When checking the refrigerant pressures in your HVAC system, the pressures are highly dependent upon the ambient air temperature.

If the a/c condenser is heat soaked (due to low air flow across the condenser caused by many things such as a worn out fan clutch) your pressure readings may not be optimal and that could result in an improper refrigerant charge and possibly even a compressor kicking off due to the high pressure switch tripping, even if the refrigerant charge is correct.

In other words, if it is hot outside, and your worn out fan clutch isn't pulling very much air through the condenser, especially at idle, your compressor may cycle needlessly and it would be very hard to make sure you have the proper amount of refrigerant in the system.

If it were me, I would confirm good airflow and go from there.

That might be all you need.

One very down and dirty test is, with the engine off, grab a fan blade and try to give it a spin.

If it spins more than 1/8 to 1/2 turn and has little or no resistance, the fan clutch is most likely done for and needs to be replaced.

It should not easily spin a couple of turns, for sure.

It makes about a quarter turn right now when I give it a yank. I'd say the fan clutch is done too.

 

[Auto Parts Guy]

I second the severe duty fan clutch. But just an additional warning, that thing is loud.

I would start with the pressures. It's hard to diagnose an AC system most times without them. Pick up a nice set if you can afford them, otherwise a cheap set is better than nothing.

While you're waiting on a set of gauges, If the AC clutch isn't turning, check the fuses, if fuses are ok, check that you're getting 12V to the clutch wire.

Does your HVAC light come on when you press the snowflake?

 

[joendoodle]

A/C compressor clutch not engaging:
In my experience, the suction pressure switch has been the failure more often than not for the clutch not engaging @ all; but here is a list of things to check.

Check: Fuses, If blown, replace, if it blows again, you have serious troubleshooting ahead.

compressor (clutch) relay, install KNOWN good relay (either new or swap with known working relay)

permissives:
Low refrigerant (suction) pressure prevents the compressor from running (to protect it) => not too hard to check pressure, if it is good then switch could be bad, a quick jumper can confirm, new switches are not expensive or hard to change. Note (did GM design do this I don't know) the A/C compressor cycles on "load, some designs use the suction pressure switch to cycle the compressor On & Off.. do not leave this device jumpered to make the compressor run more than a few seconds.
High discharge pressure, a symptom of inadequate "heat sink" (aka the fan isn't pulling enough air or condenser is too dirty) or blocked refrigerant lines.

 

[Arussell776]

I second the severe duty fan clutch. But just an additional warning, that thing is loud.

I would start with the pressures. It's hard to diagnose an AC system most times without them. Pick up a nice set if you can afford them, otherwise a cheap set is better than nothing.

While you're waiting on a set of gauges, If the AC clutch isn't turning, check the fuses, if fuses are ok, check that you're getting 12V to the clutch wire.

Does your HVAC light come on when you press the snowflake?

No clue. The unit does turn off sometimes when I turn it on.

 

[Capt.Crunch]

I was having trouble with mine, I have a 2010 Avy and when I checked it the pressure was fine, but sometimes it would blow warm air, I got a good set of guages and discovered that the high side was building too much pressure, I lowered the charge on it and it still didn't blow cold enough, I ended up pulling out the orifice tube and it was almost clogged, I installed a new one and recharged the system and it is blowing ice cubes, I even have to turn it down on hot days, I want to make it clear that I have the 2 speed electric fans on mine.

 

[Avalanche Addict]

Does the 2006 LS have a cabin air filter?

 

[ygmn]

Does the 2006 LS have a cabin air filter?

NOT as standard from Factory.

But there are kits out there to add cabin filter to system by cutting hole putting filters in and sealing up with cover from kit and screw.

 

[Wpolonavyguy]

The compressors I read tend to wear out faster than most, being too low pumps harder & fluid/oil pools?
Luckily I've only had to clean/ tinker with actuators blend door when drivers side blew hot & passengers side cold. The accumulator fill port had Schrader valve leak r134 had to fill & get Schrader valve to hold without leaking. I'd like to make a cap that can hold & seal pressure so cheap valves can't keep leaking.