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2010 Suburban 1500 LT "The Beachwagon"
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Discussion Starter · #1 ·
Hi,

I'm new to the forum and happy to see all the great information available!

I bought a used 2010 Suburban 1500 LT last September. The A/C worked when I bought it. We use the vehicle very little, mainly to drive the grandkids to the beach in the summer, but I drive it once a week or so just to keep it going.

This summer the A/C didn't blow cold. I tried a recharge, but no luck so took it to the dealer for diagnostics. They advised that the rear A/C lines were leaking. I believe "pissing out" was the phrase the service manager used:). It was estimated to be $1400 to fix. Since I only paid $9K for the truck and use it rarely, I didn't opt for the dealer repair.

After a little research I found I could buy new rear lines from autocoolingsolutions.com, so that's what I did. I got the old lines unfastened (not easy at the rear due to galvanic corrosion of steel stud through aluminum clamp/block) and installed the new lines.

AC Pro recommended filling with refrigerant prior to recharging the system. I found a Youtube on how to do it. In my case it doesn't look the the compressor clutch is engaging due to no refrigerant in the system (I'm guessing there's a sensor to prevent the compressor from coming on if no/low refrigerant). The compressor did engage before I took it to the dealer.

Can I energize the compressor manually in order to load the refrigerant by running a wire from the positive battery terminal to pin #30 on the fuse block? I'm not great at electronics and don't want to damage anything.
170059
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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Actually, do not go down that road. As you add refrigerant, the compressor should cycle on automatically. If not, a quick paperclip jumper test might be in order if there's a sensor connected directly to the refrigerant line.
 
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Reading this as I prepare to repair the rear lines on my 99 (for the 3rd time!!) due to an o-ring leak at the mid-point connection in the suction line that I found when the truck couldn't couldn't cool last week when the temps went over 32 C / 90 F (that is an almost unheard of temp in this part of the world........). This time I'm going to use a repair splice instead of the full line change as I don't think I can get the line disconnected at the rear evaporator again.......

couple thoughts....

1st - yes you can jumper the low pressure switch to pull up the compressor if it won't engage. All you need to do is short across the pins to bypass the relay. However, this shouldn't be necessary as once you start the fill it usually will come in on its own as pressure starts to build. On my 99, the compressor started to engage at the end of the 1st can , so ~1/4 full. If you do this, you want to avoid running the compressor dry for very long else you could trash it.

2nd. I don't read that you have pulled a vacuum 1st? If not, that can impair the fill / long term operation and might lead to bigger issues downstream. It's also a great way to make sure your new connections are good.

Last. Other experts on the forum can chip in, but I understand some amount of oil needs to be added to replace oil lost in the lines you took out (& any other parts you may have replaced). In my case I also changed out the accumulator so the oil was added there. I looked high and low when I did mine, I never found a good answer for the amounts held in the lines, so added a small amount to be safe. As things have been OK for several years up to this latest leak, I guess I was close enough.
 
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As @Cowboytrukr said, don't jump the compressor.
I don't use refrigerant to pressurize and leak test.
I use nitrogen or CO2 charged to 250 psi and see if it holds. You can also hear the leak. I use a liquid bubble leak solution on all connections.
In the absence of nitrogen or CO2, a vacuum test also works using a vacuum pump. If it pulls down to 30", there is no big leak. Then let it sit for 8 hrs and see if it loses vacuum to test for small leaks. But you have to make sure your hoses, fittings and gauge manifold set are not leaking.

The faster way of charging with the ac compressor off is liquid charging on the high side. Watch the low side pressure rise to about 70 psi then stop. Turn AC on. Final charge with vapor on low side with compressor running.
 
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2010 Suburban 1500 LT "The Beachwagon"
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Discussion Starter · #5 ·
Thank you all for the helpful information. I'll need to see if I can buy the necessary stuff at reasonable prices to do this myself, or maybe borrow, or rent. If not, I'll revert to local garage. I like the idea of testing with nitrogen and listening for hiss. Hopefully, the rear lines were the only problem and the system is tight now.

How much refrigerant should the system take?
Do I need to add any type of lubricant or oil?
 

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Thank you all for the helpful information. I'll need to see if I can buy the necessary stuff at reasonable prices to do this myself, or maybe borrow, or rent. If not, I'll revert to local garage. I like the idea of testing with nitrogen and listening for hiss. Hopefully, the rear lines were the only problem and the system is tight now.

How much refrigerant should the system take?
Do I need to add any type of lubricant or oil?
refrigerant amount will be on a decal under hood.

I think the oil is PAG 46, but you need to verify this. You can Google for the correct type of PAG oil if it isn't shown on the decal as well. Usually, the amounts required to be added based on what has been replaced can be found as well. The problem I had was that I could find nothing on the '99 that showed the amount just for rear line replacement.

While using Nitrogen under pressure to test is the best way to test and works well, it adds complexity to the process that you may not be able to do at home.

Pulling a vacuum using a vacuum pump and gauge set and then monitoring to see if it holds pressure is the "most common" DIY method. Most setups are good enough to manage this while leaving the gauge set connected. I've found my cheap gauge set and pump can hold vaccum overnight with no trouble. You want the system to be able to hold a vacuum for at least 30 minutes. It is also possible to pull the vacuum and then remove the set and then reconnect after a time to see if the vacuum has held - this can be more problematic as there will be some loss of vacuum as the connections are removed / replaced. Down side of the vaccum process is that minor leaks are hard to find - as you have (I think) only replaced both rear lines, then you have only a few points of potential failure, all at connections so it is a little easier to just recheck they are all good.

The reason to also replace the accumulator is that once the system is open to air, water is absorbed. Its function is to maintain the "dryness" of the system and it can be compromised very quickly once the system loses integrity. Moisture and compressors aren't good combinations......

Or, you can just go to a shop and ask them to recharge once you've got the system ready to go. I've found a lot of local shops can be (understandably) resistant to this as they can never be certain what has been done and are leery of repercussions on work they haven't done from A-Z.
 
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Keep in mind that if the clutch does not engage, and you have the appropriate pressure on the high side, your high pressure sensor may be bad. Turn on the ac and check to see that you have line voltage to the sensor. If so check the HP sensor (located on the back of the compressor). If it is not activating, evacuate the system, remove and replace the sensor. It is important to take the sensor with you when you go to the parts store/dealership. They will want to see the color, and sometimes colors fade over time. I have been down that trail and it is not fun.
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Discussion Starter · #8 ·
Just to close out this thread, I brought the vehicle to my local garage where they evacuated the system, pressure checked it, and recharged the a/c for $120. So instead of $1400 to replace the lines at the dealer it cost my $374 for replacement lines that I did myself + $120 for recharge. $494 vs. $1400 = $906 savings.
 
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