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A/C Deslugger

treegump

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From my understanding the Deslugger has been around for a while, but because I just found out about it, I'm guessing that it's not a widely known part. I thought I'd start this thread because I still have questions concerning it - outside of my vehicle thread and outside of what I could find using "search".

The Deslugger is a patented compressor clutch timer that is designed to help prevent “slugging” in low mounted compressors after the vehicle has been sitting idle for over 30 minutes or longer. Upon the next start up, The Deslugger is designed to gradually push oil or liquid refrigerant out of the compressor before it fully engages, relieving the possibility of a catastrophic system failure.

U.S. Patent No. 9,377,014

U.S. Patent No. 9,796,248


Protecting your compressor replacement job!
Compressors on many modern A/C systems are mounted low down on the engine. This location leaves the compressor prone to liquid “slugging.” When the vehicle sits, oil and liquid refrigerant collects in the compressor body. The result can be hydraulic lock with catastrophic compressor damage on initial compressor engagement. Four Seasons Problem Solving Part, the Deslugger, eliminates this issue.

Extend compressor life by eliminating liquid "slugging" with the Four Seasons Deslugger!
The Four Seasons Deslugger solves this liquid “slugging” problem by pulsing the compressor clutch multiple times during initial engagement. By gradually engaging the compressor, trapped liquid is gently moved out, preventing catastrophic hydraulic damage. Once the brief deslugging function is complete, the compressor reverts to normal cycling operation until the system has been off again for more than 30 minutes.

 

treegump

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I now understand what a deslugger is, both from several members here and the above website.

To continue my understanding:
- If I plug this into my compressor before getting it swapped out at 250k miles it shouldn't explode even if it fails? Or can the compressor still lock-up with a deslugger.
 

Will L.

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The Deslugger hurts only the wallet to buy it. Many many years down the road if the a/c fails to turn on the compressor you can bypass it to see if it failed. It’s electronic and can fail but I see no reason it should anytime soon.
The technology is used all the time in big, and I mean BIG electric motors for industrial use. The programing in Variable Frequency Drives commands the power on in lower levels and slowly ramps it up using a couple of jolts to push the heavy load as needed. Someone just took that way expensive and very needed technology and made an affordable version for car a/c systems.

It could help extend the life of the compressor and shouldn't do anything to shorten it. I mean, to be technical having the clutch engage 2 extra times each first start means the clutch material will wear out sooner, but since the compressor cycles in it’s start then the internal compressor see less load, even when not too full of oil or liquid refrigerant.
 

ak diesel driver

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I thought my compressor was siezed up it would shred the belt the instant you turned it on. When I swapped the engine out I discovered it was fine. Makes me wonder how many pumps were changed for no reason
 

Rockabillyrat

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Depending on the year GM had several TSB's for belt issues, and compressor noises. One was an inlet filter, the other was a PCM reprogramming.

Most of the time I see issues from either too much PAG oil or not enough. Vehicles that get charged multiple times seem to get a little dye added every charge. Over time it adds up and hydrolocks the pump.

If the deslugger was an important upgrade I would imagine I would have seen at least one over my career. I never even heard of it until this post. Maybe my location has something to do with it being in a northern state.
 

Will L.

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That could be. Kinda popular in the southwest where a/c runs 9 months of the year.

Absolutely over or under charging with oil, dye or refrigerant can kill a system. But on the ones where the oil drains down into the compressor the problem gets amplified.
 

Rockabillyrat

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The a/c compressor does run anytime a vehicle is in defrost. Its air "conditioning" not air cooling. So the a/c runs year round and most people don't realize that. But in a hot climate state it will work harder year round. We hardly see 90* temps up here in the summer.

Almost every modern vehicle runs the compressor on the bottom. They use PCM programming to prevent compressor damage.

The way I see it, if your vehicle has a low mount compressor and you live in a southern state. MAYBE the deslugger is a good idea. I'd confirm there isn't a factory TSB addressing the issue first. Just trying to give my real world experiences.
 

WarWagon

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The PCM doesn't do ANYTHING to help stop damage from a liquid slug the compressor has to eat. As noted elsewhere GM redesigned the compressor drive with a PIA to install stretchy belt and eliminated the AC belt tensioner. GM also redesigned the rear evaporator, in 2002, to dump into the accumulator (finally like just DUH!) rather than a straight slug shot to the compressor.

I have had many GM AC belts break on startup from slugging. Attached PDF shows a slugged split in half compressor. Maybe one shouldn't turn on the AC at 65 MPH pulling a grade for the first time... 🤪

The hotter the cabin (evaporator) and condenser are on shut down the more refrigerent can condense in the compressor on cool down. Because the compressor is in the cool air coming up from the bottom as things cool off. It's not just "oil" as the video suggests.

The deslugger simply starts and immediately stops the compressor like 3-4 times to clear the liquid out. And this is the important part: it ELIMINATES the "THUMP!" many low mount AC systems are known to have randomly on startup. That is replaced with the clunk, clunk, clunk of the compressor kicking in.

Some compressors extend the warranty with a deslugger purchase.

Some systems are better than others as they don't make one for the 2003 Dodge I had. It would thump good now and then while the OEM Sanden compressor made it 150K and 15 years. GM systems on the 5.3L hardly make it 3 years out here.
 

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Rockabillyrat

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The PCM can be programmed to start and stop the compressor a few times on initial start up. Not sure if that's was that GM did in their reprogramming TSB they issued. But that is what alot of other manufacturers do.... I've had training classes talking about it.
 

WarWagon

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Any specific PCM reprogramming to the GM years in question? IMO if 4S has a listing for a deslugger for a specific vehicle it should work and not have any PCM programming in the way.

Quick and dirty way to tell is if the compressor turns on and stays on without any cycling in the first 10 seconds during the first start of the day = no PCM programming that matters to the deslugger operation. Thus it's safe to use it.
 

Rockabillyrat

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I can't seem to locate the TSB for the reflash. I'm going to say it was somewhere in the mid to late 00s. I will try to look at work.

But while I was searching for that I found a TSB I hadn't seen before. The 02-04 trucks got a updated compressor for slugging issues. So I assume any GM after that got the newer compressor design.

It's not that the deslugger is unsafe to use. The way I see it is why use a aftermarket bandaid product if there is a update or replacement part that correctly fixes the issue. It's a snake oil product in my opinion. But if you want to run one it wont hurt anything other than your wallet.
 

Rockabillyrat

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I do remember the reflash having to do with a compressor noise on a hot restart with ambient temps above 95*f. I was too late to edit my previous post.
 

Will L.

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How would it be a snake oil product? Cycling the compressor is like cycling any pump that has to deal with heavier accumulation at start up than it does during normal operation. That is a super common thing to do in many industrial motor/pump applications. If gm made a program in the komputr to solve it, that would be acceptable but since it is a stand alone program it isn’t ok?

The design flaw is having the compressor mount too low. A redesign of the compressor is ok too, if it is proven to actually solve it. But like many gm goofs, fix #1 was the accumulor change they ditched right away, then the stretchy belt, then compressor redesign, whats next?
Like the 6.5 overheating fixes- how many thermostat crossovers, restrictors, holes in bumpers, waterpump changes, eventually they got it ok... sort of.

Dead cylinder for mpg improvements in the 5.3 and 5.7 that was so plague ridden they kept changing the name of how many times to say the newest year was a wazoo thing and not the compression killing issue of last years...

When the mfr makes a poor design decision and doesn’t come up with a “once for all” fix right out the gate- I think it is wise to go aftermarket. Like a pmd on a heat sink way away from the heat of the engine. GM however STILL says put a new pmd directly on the ip...
 

Rockabillyrat

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After 16+ years of working on an estimated 10,000 vehicles I have never seen a deslugger. Not one person I asked at work has seen one. Most of them laughed at it when I brought it up at lunch and said that's what the PCM is for. I have seen so many GM trucks come in with over 200k on the original compressor. If it was a necessary fix believe me I would have installed one by now. Or would have at least heard of one. Sounds like its just a waste of money and time to me... Now I will agree GM had a slugging issue on the gmt800 trucks. That is clear due to a TSB they released about it. The first fix was an updated compressor. Later they fixed it with an inline filter. From the training classes I've had through work GM and other manufacturers program the PCM to handle the slugging issues of low mounting compressors. Pop the hood and any modern car or truck, they are all located on the bottom. The deslugger is built into the PCM programming. No reason to add one at that point.

On the early GMT800 that had the issue (02-04) if you have the original compressor, then maybe it's a good idea to add a aftermarket deslugger. Or you could install the updated parts and also fix the issue.

I did find the reprogramming TSB and it was for the 07-08 trucks. So GM fixed the issue on later trucks with PCM programming. Then had to make an update to it for having issues above 95*.

We are talking AC compressors here. Yes you can bring up the DOD issues. Or the over heating issues of the 6.5. The 6.5 was a low budget engine that had multiple design flaws. With the DOD I see one common use. Lack of maintenance from the owner. Correct oil, changed at the right time is key to making them last. Not to mention the acceptable oil consumption on the newer engines is 1 qrt per 1000 miles. If you go 3k on an oil change then it could be 3 qts low on oil. NO ONE CHECKS THEIR OIL ANYMORE!!! That does a number on the DOD system. That being said if I was stupid enough to own one I would tune it out with EFI live. Even with proper maintenance it's a stupid design I will agree with that.

I'm not trying to argue so don't take what I say the wrong way. With my hands on experience I just see the deslugger as a snake oil product that you just don't need. There are just as many useless aftermarket products out there as flawed factory designs. Remember the tornado that went inline with the air duct? Of course there are plenty of good aftermarket products that fix manufacturer problems. I don't think a deslugger is one of those.
 
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THEFERMANATOR

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Up north most AC's do not run all the time, not even on defrost. Yes the ac function is enabled in defrost, but if the temp is below 40-45 degrees, the compressor will not engage.

I live in the southeast where AC is used YEAR round(even in winter our daily highs get into the 80's and sometimes 90's). I've heard of the deslugger, but I have not heard of anybody using one successfully. The stretch belt is considered by most to be the fix.

GM did change compressors in 00/01. The first gmt800's got the infamous ht6(belly leaker) and GM learned real quick they wouldn't work. Then GM came out with the Denso compressors in 2 different displacements for trucks/and full size suv's(the trailblazer got a completely different compressor due to space constraints). The programming changes all had to do with compressor off time. They made it so there was a longer off time between cycles at higher intake air temps.

If slugging was such a big issue, I guarantee you there would have been major lawsuits because AC is one thing most drivers won't live without. And I also find it odd that you only hear about it on truck/suv's when GM AND most other manufacturers have been mounting compressors as low as possible on cars, vans, and everything else without slugging ever being an issue.
 
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