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suburban with black death

blacksuburban on Mon July 19, 2010 1:21 PM User is offline

Year: 1994
Make: Chevy
Model: Suburban
Engine Size: 350
Refrigerant Type: R134

i have black death. It has been there from the factory. Apparently the first year (1994) they converted to R134 someone goofed up and i ended up with a black death AC. I have replaced compressors every year. I just replaced the condenser, compressor, accumulator, orifice tube and expansion valve (it has rear AC also). I was told I didn't need to replace the lines or the two evaporators. I flushed those parts with ac flush and clean using shop air (80 to 100 psi) repeatedly (10 to 20 times for each component circulating in both directions). There is still some black soot sticking to the walls of the tube ends (what i can reach). I have to assume the whole system still has the soot in it. i have been filtering the flush liquid and it still comes out with some fine black dust.

So, do i put it back together and use it? I really don't want to replace the evaporators if i don't have to (a big pain). Plus it will cost another 500 dollars for parts (lines are about $250 alone).

Thanks for any help.

GM Tech on Mon July 19, 2010 1:26 PM User is offline

Has the TSB ever been enacted?

Knocking TSB for 94/95 Suburbans

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

blacksuburban on Mon July 19, 2010 1:34 PM User is offline

OK. The question though is whether the black soot residue i cant flush out is going to kill my new compressor.

Cussboy on Mon July 19, 2010 3:17 PM User is offline

If it helps, here's my AC history with my R134a 1994 GMC Suburban, in Arizona, a real test temperature-wise.

Bought it in late 2000 with about 80K miles; AC worked OK but compressor was making a little noise and R4 compressor was leaking a little oil out its body (see that TSB, which we didn't know about then), so I told original owner not to fix, accepted lower price.

Spring 2001 my mechanic replaced the R4 compressor with new, also new orifice tube and new accumulator, I stayed the whole morning and watched. Because the orifice tube was pristine, mechanic said he didn't need to flush the system. AC worked fine.

A few years later, belly leak in compressor, so repeat of above by the mechanic.

A few years later, low on refrigerantleaky hose crimp in the high pressure hose from compressor to condenser. I replaced the entire manifold assembly with a new one (one high pressure and two low-pressure lines, because of dual-air), evacuated and filled with R134a.

A year later, rear AC stops being cold, Mrs. Cusser doesn't even notice, good cooling for front and 2nd row passengers. We take to California in September 2009 for vacation, after returning Mrs. Cusser takes 6 people on 112F day to see a play, I asked about the temperature, and she said a few got too cold. I took off all the rear evaporator box covers to take a look-see (after GM Tech told me that GM would not do such TSB repair for free) decided NOT to "go in" and replace the rear expansion valve, as no added value to me, and the '94 Sub was actually only worth like $2500.

A few months later, the refrigerant had leaked out (yes, one uses the AC in Arizona in December and January), mechanic looked at it while in for something else, said compressor was leaking again (R4 are known for this, especially in dual-air applications, see TSB).

March 2010, I bought a new accumulator because it had without refrigerant a few months and a brand-new Delphi R4 compressor. I didn't want to throw the dollars into a Sanden or other replacement, as that would be more expensive, would require mounts and new hose attachments as well, and I doubt I would have the Suburban long enough to make that worthwhile, remember worth=$2500). I install those, with 8 oz. of refigeration oil containing UV dye, as zero oil came out of my old compressor. I added about 65 oz. of R134a, AC works fine to this day. The rear AC still doesn't work, no big deal; even the rear heater is now capped off with a small U-shaped hose under the passenger door, as those special GM fittings started to leak anti-freeze (thanks, GM !!!), so I just figure the rear expansion valve is either clogged, or just stuck closed, no an issue for me.

So I've never had either evaporator or the condenser replaced. And I have not done the repair in the TSB either. 207K miles and counting, the AC is still very cold.

Edited: Mon July 19, 2010 at 3:20 PM by Cussboy

iceman2555 on Mon July 19, 2010 4:34 PM User is offlineView users profile

It would be very interesting to know what type flush chemical is being utilized for this repair?
The issue with 'Black Death' has been applied to numerous compressor failure/issues of the years and actually has not bearing on the original 'Black Death' failure of Fords. This was a product failure that can be contributed to one compressor...the FX15. The issue as the construction of the swash plate and material used.
This issue does not appear in replacement Ford FS10, FS18, FS 20 or later units. This issue has been resolved by Ford.
The subsequent failures contributed to 'Black Death' are associated with additives, lubricant failures and possible residual flush chemicals. Residual flush chems are the primary cause of this secondary 'Black Death' issue.
Unfortunately, the system can be flushed and cleaned to the max and if residual flush or residual contaminated lubricants remain...the issue re appears. Keep in mind that an AC system is self cleaning. The refrigerant is a great cleaner and operational conditions of the system enhance this ability of refrigerant to 'self clean' the system.
Insure that a good flush is being utilized....fast evaporating chems are not going to adequately clean this system. The flush should remain in a liquid in/liquid out to properly remove all traces of the contamination. The system must be air purged to remove all traces of possible residual flush. Take it for granted...there will be residual flush chemicals within the system.
The systems can be cleaned....it simply takes the correct chemical and correct procedure to accomplish this task. The 'ole' blow thru can with 8 + oz of flush is simply not adequate to clean this or any modern AC system. This procedure simply does not produce a sufficient volume of chemical.
The answer to your question....the dark material should be removed from the system....it may re contaminate the system and the process begins once more.
There have been instances where the entire AC system had to be replaced !!! Hopefully this will not occur with your system....but this material can be a b*&^h to remove.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

HECAT on Tue July 20, 2010 7:05 AM User is offline

Quote
Originally posted by: blacksuburban
i have black death. It has been there from the factory. Apparently the first year (1994) they converted to R134 someone goofed up and i ended up with a black death AC. I have replaced compressors every year. I just replaced the condenser, compressor, accumulator, orifice tube and expansion valve (it has rear AC also). I was told I didn't need to replace the lines or the two evaporators. I flushed those parts with ac flush and clean using shop air (80 to 100 psi) repeatedly (10 to 20 times for each component circulating in both directions). There is still some black soot sticking to the walls of the tube ends (what i can reach). I have to assume the whole system still has the soot in it. i have been filtering the flush liquid and it still comes out with some fine black dust.



So, do i put it back together and use it? I really don't want to replace the evaporators if i don't have to (a big pain). Plus it will cost another 500 dollars for parts (lines are about $250 alone).



Thanks for any help.

It's not black death, it is carbonized (cooked) PAG oil. Some of it will penetrate the aluminum surface like anodizing, this will not flush away, but will do no harm to the thermal transfer abilities or recontaminate the assembled system. However the surface soot (fine black dust) must be removed. The continued appearance of this dust after repeated flush attempts indicates a flaw (no disrespect intended) in the method and or chemical being used to flush. The chemical you mentioned is a POE base product that leaves considerable POE non-evaporative base behind after much drying. To properly clean these components and line sets, they have to be flooded and flowed with high volume liquid to apply the forces necessary to carry away solids of any kind. A suitable chemical that can dissolve the oils and binding substrates to release these particulates will be required; and that chemical must be capable of being blown dry to laboratory trace levels.




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