Sanden 4440 install

[hekg]

Vanula escaped from the laboratory today for a while. I drove it around for close to 1 hr. The newly built and replaced steering box and front sway bar end links made it drive like a dream. It was sunny and 97°F. A/C was blowing the the 30s as long as I was moving. After 10-15 minutes I had already knocked the blowers down to medium low up front and turned the rear off. After 20 minutes I had to knock the recirculate off as the air was so cold it was freezing my knuckles on the steering wheel. I eventually set it to Bi-Level even and it was still an icehouse inside the van.

You must be registered for see images attach

Wow that's awesome! I wish my ac was cooling anywhere near discomfort for me. Here in south florida it's around 90 degrees today but it feels like 105 easily.

When I finished putting in the 48oz I had the air on full blast in the front and in the rear. It was also on recirculate with very little airflow at the condenser. Engine rpm was at around idle which is around 600-800.

I tested the temp at the vents with an infrared thermometer and got around 60 degrees.

 

[L31MaxExpress]

Wow that's awesome! I wish my ac was cooling anywhere near discomfort for me. Here in south florida it's around 90 degrees today but it feels like 105 easily.

When I finished putting in the 48oz I had the air on full blast in the front and in the rear. It was also on recirculate with very little airflow at the condenser. Engine rpm was at around idle which is around 600-800.

I tested the temp at the vents with an infrared thermometer and got around 60 degrees.

Do you have the 11 blade plastic fan or the 5 blade steel? With the engine fully warmed up and the ac on, let it idle ~5-10 minutes, bring the engine up to 2,000-2,500 rpm. Does the fan roar from the clutch being engaged? The factory 11 blade plastic fan moves a fair amount of air as long as the clutch is coupling when it is hot.

 

[AuroraGirl]

Wow that's awesome! I wish my ac was cooling anywhere near discomfort for me. Here in south florida it's around 90 degrees today but it feels like 105 easily.

When I finished putting in the 48oz I had the air on full blast in the front and in the rear. It was also on recirculate with very little airflow at the condenser. Engine rpm was at around idle which is around 600-800.

I tested the temp at the vents with an infrared thermometer and got around 60 degrees.

Lock the fan clutch in "full on" by playing with the spring, you "unhook" it from the thing that holds one end still, then you turn it all the way to the extent of its travel and then it will be a almost like you dont have a fan clutch(full CFM)

But it only works if you have a viscous one

 

[hekg]

Do you have the 11 blade plastic fan or the 5 blade steel? With the engine fully warmed up and the ac on, let it idle ~5-10 minutes, bring the engine up to 2,000-2,500 rpm. Does the fan roar from the clutch being engaged? The factory 11 blade plastic fan moves a fair amount of air as long as the clutch is coupling when it is hot.

I actually also just replaced my fan clutch to a heavy duty acdelco, it's pretty loud now compared to the old one but that's ok. Also, my fan is the 11 blade plastic fan so it is moving alot of ai.

So next I should rev the engine to 2500 rpm while adding the last 12oz bottle? At what point do I determine that I've added too much and the full 12oz bottle is not necessary?
Big thanks to everyone for all of the tips!

 

[L31MaxExpress]

I actually also just replaced my fan clutch to a heavy duty acdelco, it's pretty loud now compared to the old one but that's ok. Also, my fan is the 11 blade plastic fan so it is moving alot of ai.

So next I should rev the engine to 2500 rpm while adding the last 12oz bottle? At what point do I determine that I've added too much and the full 12oz bottle is not necessary?
Big thanks to everyone for all of the tips!

Do the last can at 1,500 or so watching the pressures. 300-375 is not unusual in your weather. You will know when to stop charging when the line coming off the accumulator starts to get cold and starts sweating.

 

[hekg]

Do the last can at 1,500 or so watching the pressures. 300-375 is not unusual in your weather. You will know when to stop charging when the line coming off the accumulator starts to get cold and starts sweating.

I haven't added the last can yet but even before I finished adding the 48oz the line coming out of the accumulator felt very cold and sweaty already.

I'm going to add the last can slowly while wetting the condenser and reving the engine to around 1500 rpms then.

 

[hekg]

Hi all, my Tahoe blows nice, cold air (not super cold) when I'm driving fast down the highway AND I if I have the rear air on max fan. If I turn off the rear airt then the front air starts to blow alot warmer, almost to the point of discomfort until I turn on the rear air on max again.

Why in the world would this be happening?

 

[L31MaxExpress]

Hi all, my Tahoe blows nice, cold air (not super cold) when I'm driving fast down the highway AND I if I have the rear air on max fan. If I turn off the rear airt then the front air starts to blow alot warmer, almost to the point of discomfort until I turn on the rear air on max again.

Why in the world would this be happening?

Are you sure you do not have a bad cycling switch? I have seen them fail and cycle the compressor off in the 45-60 psi range instead of the low 20 psi range they were calibrated for. Short cycling of the compressor with the rear air off would explain the warmer vent temps. I use the 93-95 G20 van cycling switch because they are more reliable and adjustable. They have the same thread as the OE switch where it attaches to the accumulator and only the connector pigtail needs to be swapped to use one. You can back off the set screw 1/4 turn at a time until the evaporator starts to freeze and you experience loss of cooling and airflow, then tighten it up 1/4 turn to stop it.

 

[L31MaxExpress]

These are the part numbers I use to swap to the adjustable switch. I adjust the cutout to deliver maximum cooling since I live in an oven known as Texas.

You must be registered for see images attach

You must be registered for see images attach

 

[hekg]

Are you sure you do not have a bad cycling switch? I have seen them fail and cycle the compressor off in the 45-60 psi range instead of the low 20 psi range they were calibrated for. Short cycling of the compressor with the rear air off would explain the warmer vent temps. I use the 93-95 G20 van cycling switch because they are more reliable and adjustable. They have the same thread as the OE switch where it attaches to the accumulator and only the connector pigtail needs to be swapped to use one. You can back off the set screw 1/4 turn at a time until the evaporator starts to freeze and you experience loss of cooling and airflow, then tighten it up 1/4 turn to stop it.

I had not considered the cycling switch because I put a new one in when I did the entire job but it sounds like I should be using the one you're recommending anyway.
I was thinking more like it might be a low refrigerant situation. When I was charging it for the first time, I received conflicting amounts needed for my Tahoe and in the end I was just guessing so I don't even remember how much I put in there to be honest and it never really cooled great. First timer here of course.

I was even thinking of evacuating and vacuuming it and recharging it from scratch. Do you know the correct amount of refrigerant needed for the 99 Tahoe with rear air?
I will go ahead and order that switch though, I like the fact that you can adjust it. Thanks.