AC help, please!

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1998_K1500_Sub

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Correct Just the hose and dryer and orifice

I'm getting into a gray area here, I've rarely (4-5 times) had to re-balance a system's oil. Usually I start "from clean". But,...

Let's keep in mind the system's target oil capacity is 8oz. I assume you had a proper 8oz oil charge prior to the uncontrolled blowdown.

From the GM document I posted above:

- add 3oz to backfill for the oil lost due to uncontrolled blowdown
- add 3.5oz of oil to replace that in the receiver / dryer (to make up for the oil coating the desiccant and the inside of the canister)

At this point, the suggested addition of oil is 6.5oz... only 1.5oz short of a full charge

So let's now consider the oil which might be resident in the other components.

The same GM document suggests that 3oz might be resident in the evaporator. Adding that to the 6.5oz from above yieilds 9.5oz. OK, that's over the 8oz target, but better a little over than under IMHO.

You might drain the compressor just to see how much is in it, but if it was running at the time of the blowdown (which I assume was the case) there's probably not a lot within (the HT6 doesn't have a "sump", so guessing 1.5-2oz of oil remains based on information I have from Sanden; see the picture below).

Net-net from me: Follow the two steps given above (add 3oz plus another 3.5oz to the system). I would put it ALL in the receiver / dryer so it's close to the compressor, i.e., it will reach the compressor soon after start up. Alternatively, you could split the additions, i.e,. 3.5oz in the R/D and 3oz added to whatever's in the compressor (pour it in the suction port, then turn the compressor by hand 10 times to circulate the oil around a bit so it doesn't hydrolock when you first re-start it).

That's my $0.02.

@PlayingWithTBI and @L31MaxExpress, to name but two, might weigh-in here. They speak well when it comes to AC.


NOTE:

Here's a snippet from the Sanden SD Compressor Service Guide V2 which gives some insight into the expected oil amounts to find resident in the compressor, based on compressor RPM (on a GMT400, the compressor turns at about 1.5x engine RPM, assuming an 8" crank pulley and a 5.2" compressor pulley). Find the details yourself in the Sanden document (attached as a .pdf).

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TCBRacer77

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I'm getting into a gray area here, I've rarely (4-5 times) had to re-balance a system's oil. Usually I start "from clean". But,...

Let's keep in mind the system's target oil capacity is 8oz. I assume you had a proper 8oz oil charge prior to the uncontrolled blowdown.

From the GM document I posted above:

- add 3oz to backfill for the oil lost due to uncontrolled blowdown
- add 3.5oz of oil to replace that in the receiver / dryer (to make up for the oil coating the desiccant and the inside of the canister)

At this point, the suggested addition of oil is 6.5oz... only 1.5oz short of a full charge

So let's now consider the oil which might be resident in the other components.

The same GM document suggests that 3oz might be resident in the evaporator. Adding that to the 6.5oz from above yieilds 9.5oz. OK, that's over the 8oz target, but better a little over than under IMHO.

You might drain the compressor just to see how much is in it, but if it was running at the time of the blowdown (which I assume was the case) there's probably not a lot within (the HT6 doesn't have a "sump", so guessing 1.5-2oz of oil remains based on information I have from Sanden; see the picture below).

Net-net from me: Follow the two steps given above (add 3oz plus another 3.5oz to the system). I would put it ALL in the receiver / dryer so it's close to the compressor, i.e., it will reach the compressor soon after start up. Alternatively, you could split the additions, i.e,. 3.5oz in the R/D and 3oz added to whatever's in the compressor (pour it in the suction port, then turn the compressor by hand 10 times to circulate the oil around a bit so it doesn't hydrolock when you first re-start it).

That's my $0.02.

@PlayingWithTBI and @L31MaxExpress, to name but two, might weigh-in here. They speak well when it comes to AC.


NOTE:

Here's a snippet from the Sanden SD Compressor Service Guide V2 which gives some insight into the expected oil amounts to find resident in the compressor, based on compressor RPM (on a GMT400, the compressor turns at about 1.5x engine RPM, assuming an 8" crank pulley and a 5.2" compressor pulley). Find the details yourself in the Sanden document (attached as a .pdf).

You must be registered for see images attach
Wow! I’m blown away! Thank you very much for all the help! I will update this thread when I crack into it this week! Very thankful!
 

1998_K1500_Sub

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Something came to mind.

PAG is hydroscopic as you likely know [note 1].

If you sealed off your system shortly after the hose broke to prevent breathing (e.g., wrapped the wound well with electrical tape), then "good for you".

If instead the system's been left with an open wound for an extended time, and / or in a high-humidity environment, I would want to study the situation further and decide if it's not better to flush the system entirely to rid it of oil that's been exposed to moisture.

AFAIK, when PAG takes up water, it is permanent; it can't be removed with vacuum so it remains in the system. Too, the character of the oil is altered [note 2].

(I may edit this to add additional info)

NOTES:

[1] "Double end capped" PAG oils are available which are relatively less hydroscopic but they're more expensive than "single end capped" conventional PAG. The latter is common as a service item; the former is typicallly a special-order item and is used by some OEMs. See https://autoacforum.com/messageview.cfm?catid=2&threadid=11397

[2] See "PAG oil" here: https://www.delphiautoparts.com/usa...l-why-quality-and-quantity-are-both-important "When PAG oil and moisture mix, they react, creating an acid that can corrode and damage system related components. For this reason, PAG oil should never be used to lubricate O-rings, compressor shaft seals or refrigerant line joints"
 
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PlayingWithTBI

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@PlayingWithTBI and @L31MaxExpress, to name but two, might weigh-in here
Hello!

Lots of great info here @1998_K1500_Sub

Personally, I'd pull the compressor, drain it, pull the Receiver/Drier, orifice tube, flush the rest of the system, and start over but, that's me. O.P. is already 1/2 way there why not? Then you know exactly how much oil you have plus, its fresh and new (whatever viscosity you want to use). Rather than taking a chance with a saturated and/or contaminated system. I live in the desert and would rather not have it fail on me when it's ~120° out in the middle of BFE :cool:
 

1998_K1500_Sub

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Personally, I'd pull the compressor, drain it, pull the Receiver/Drier, orifice tube, flush the rest of the system, and start over but, that's me. O.P. is already 1/2 way there why not? Then you know exactly how much oil you have plus, its fresh and new (whatever viscosity you want to use). Rather than taking a chance with a saturated and/or contaminated system. I live in the desert and would rather not have it fail on me when it's ~120° out in the middle of BFE :cool:

I do like to start with a fresh system because then you know what you're working with. But I don't enjoy flushing because I don't have a handy source of clean (or dry) air... or any other gas in sufficient quantity and pressure (e.g., nitrogen, gaseous R134a, ..., propane :oops:) to blow out the flush. Too, I don't like flushing condensers (I never have in fact, I always replace) because it's difficult to do well IMHO unless they're removed.

If OP taped up his high-pressure hose after the blowdown, and if the orifice tube's clean (that's two "IFs" there), then I guess it's up to him to either do it piecemeal or flush-and-start-anew, depending on how he weighs the tradeoffs of either approach.

Otherwise, I think your solution @PlayingWithTBI is his only good solution (including a condenser and compressor replacement if the orifice tube's dirty).

That's my $0.02 anyway. I always value your perspective.
 
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PlayingWithTBI

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But I don't enjoy flushing because I don't have a handy source of clean (or dry) air... or any other gas in sufficient quantity and pressure (e.g., nitrogen, gaseous R134a, ..., propane :oops:) to blow out the flush.
You can get a coalescing filter to help dry the air if you don't have a refrigerant drier but, I really don't have an issue with using shop air, I do normally evacuate the system overnight. The last thing I uncap and install is the receiver/drier before sucking the system down.

I don't like flushing condensers (I never have in fact, I always replace) because it's difficult to do well IMHO unless they're removed.
I've done both and, agree on a new condenser, especially if you get a parallel flow one. It's always nice to go all new but, some folks can't afford to. Sometimes it's a trade off.
 

1998_K1500_Sub

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You can get a coalescing filter to help dry the air if you don't have a refrigerant drier but, I really don't have an issue with using shop air, I do normally evacuate the system overnight.

I'm "with you" on "evacuating overhight", as it should take out whatever water may have been introduced by the shop air. My other (unstated) concern is that the air hoses we use have had, or may have had, "oilers" on them. Yes, I know, the answer is to get a new air hose and mark it specifically for "non-oiler" use, but I haven't done it.

So I'm getting motivated; I should get a filter assy and a new hose to dedicate to the task.

The last thing I uncap and install is the receiver/drier before sucking the system down.

Roger that. I always start with new, sealed oil as well and install it as late in the process as I can. I use double-end-capped oils when I'm working with a clean system, otherwise I try to match the oil that's in the system if known.
 
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pressureangle

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I can't say how many hoses I've replaced that popped right at that joint or just below it. Most often, it's caused by someone removing the compressor without taking the hoses off and laying it on the fender or battery box to get at something on the motor. These hoses cannot be kinked or twisted without injuring them. There's no chance the oil did it, and if I recall correctly you can use PAG 150 where 46 is called for. Not too hard to research. I just put PAG 150 in my brand new R4 system and it's fine.
 

TCBRacer77

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just and update to a kind of dated post,
I FINALY got this fixed lol. Been several days now with ice cold ac and no issues/noises and good pressures on gage. All I did was replace the hose, replace orifice (which old one came out clean), replace dryer/receiver, and added about 5-6 ounces oil split between compressor (spun oil in) and dryer. Took a charge and so far no leaks and no concerns with compressor. I am currently working on building my L33 alum. Block 5.3 for the ls swap, so I’ll plan on replacing everything in front of the condenser anyway at that time. That’s why I didn’t really bother with the flush, just gambled this time around to save some time and get me through the rest of this spring/summer whatever lol.

Also, I had a wiring issue I was wondering if anyone else has come across… the high pressure switch on the back of the compressor, doesn’t like to fit with any of the “matching” pig tails I’ve tried. You have to notch out the connector on pig tail and the last one I had didn’t make a good connection. So it wouldn’t work most of the time. I got lucky that this new switch and my existing pigtail fit snug enough to hold (so far). I found the issue by jumping the low side and the compressor wasn’t kicking on until I tried jiggling that high side switch connector on a whim. Fixed now tho!
 
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