AC Compressor Deslugger

[Tuesdak]

Does this apply to specific compressors that "can't take it"? With all the commotion and noise that happens when I turn on the AC in my 2003 I am sure it suffers from slugging. Known what it is for 15+ years and this is the first time I have seen it be a problem. I always figured the clutch slipped enough during this condition that it wasn't an issue.

That is till I started working on another ride that is known for breaking the tensioner and belt for the compressor let alone ruining the compressor. (Compressor can depart the engine in fragments.) Currently it has bent rods and won't get over 150 PSI on the high side. (Needs 250). The parts book recommends a deslugger for it. The same 'book' doesn't recommend it for the 2003 Dodge.

So is it a weak compressor design that needs it or would both benefit form it?

EDIT: updated link.
http://www.4s.com/en/marketing/-psp-solutions/the-deslugger/#_marketing_

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’ new Problem Solving Part, the Deslugger™, solves this problem.

Four Seasons’ Deslugger™ solves this liquid “slugging” problem by pulsing the compressor clutch in brief, millisecond bursts 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.

 

[JR]

I don't think slugging is a normal operation in a system that is performing properly. I've heard of moisture and other contamination indirectly causing this issue. Here is a good article from Sanden.

http://www.sanden.com/moisture.html

Just reinforces why the replacement of the drier and proper evacuation of the system is so critical to the long term operation of an a/c system.

 

[DavidC]

I just changed the compressor on the wife's Toyota (69k miles). After it was done for a few hours and during the recharge the clutch went thru a tizzy of off/on very fast. It definately freaked me out and wondering what the heck was going on. It is a new 4 Seasons compressor from Rock Auto. After it ran for a while the clutch engaged full time and all was well. I had vacuumed and charged using a scale so I was really bewildered as the clutch was the defect on the stock Denso. I did not read anything in the instructions or on Rock Auto's site about deslugging but it does exactly as you say. Who da thunk :-laf

Dave

 

[DavidC]

Guess I should have looked at the links first. I thought it was built into the compressor, guess I will keep an ear on her compressor and see if it does it again. I started it the other morning with gauges and freon ready and wouldn't ya know it, it worked perfectly.

Dave

 

[Tuesdak]

Again this is specific to a design defect where liquid freon and oil pool in the low mount compressor causing a hydrostatic lockup as the built up liquid freon has to be forced out of the cylinders through the valves. The system in perfect working order in a off state has gas condense and drain into the compressor, a problem high compressor mount systems didn't have. It affects Honda's, Chrysler minivans, and GM stuff. GM has TSB's describing this condition as normal otherwise they would have to properly design the AC/belt system with the compressor high on the engine not on the bottom.

The symptom is a intermittent loud thud as the compressor kicks on after sitting awhile. Extreme examples are the loud thud and parts depart the vehicle from the drive belt, tensioner, to shattered compressor.

So my question is related to the low mount compressor we have on the 5.9 - is our system immune to the liquid slugging by design, hose routing, or better compressor?