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Debris in orifice tube -Hecat?

Drake57 on Sat August 15, 2015 10:56 AM User is offline

Year: 1995
Make: Ford
Model: Contour
Engine Size: V6
Refrigerant Type: R134A
Ambient Temp: HOT

Alpha compressor on car got loud, then just quit cooling. After removing compressor, input shaft freewheels, no output of any sort.

The screen on the input side of the orifice tube is heavily coated, if not clogged with silver colored particles, ranging in size from a fine dust, to maybe 0.5 mm.

I have not flushed or blown condenser. The obvious question is, whether or not to replace condenser.

This car has a parallel tube condenser, if I understand, it is not easy to tell if, or to what degree it is clogged.

Current replacement is the second (Alpha) compressor I've put on this car. Obviously, my results with first are disappointing: compressor was noisy for several years, beginning within months of original replacement. At that time, I replace all o rings, flushed with lacquer thinner, purged with nitrogen, installed new orifice tube and drier, evacuated, and charged, did not take any short cuts, nor am I so inclined this time around. It is possible that some lacquer thinner remained in system, I could still smell lacquer thinner while purging and evacuating.

I am open to suggestions, I do not mind replacing *condenser* it that is recommended. I'd rather not change evaporator. Is there really any way to tell if replacement is necessary for either? Given the apparent contamination (silver build up at o tube input), what else if any thing is recommended?

Thanks, Drake.

Edited: Sat August 15, 2015 at 10:25 PM by Automotive Air Conditioning Information Moderator

Drake57 on Sat August 15, 2015 8:41 PM User is offline

Ok, the flush expelled from evaporator looks like thin silver metallic paint, it is laden with fine (presumably aluminum) metallic particles, and a few black specks. It seems near impossible to completely flush evaporator. Cost for new is quite reasonable, but the job of R & R seems daunting.

Can anyone say if the accumulator will serve to catch any particles in flow? Something tells me no. Also, if anyone has replaced evap on Contour, how much pain is it?

So if any pro's would like to weigh in, I'd love to hear. I already have new compressor, o tube, accumulator, and plan on ordering condenser, already drained manufacturer oil charge and replaced w DEC PAG 46. It seems like I may as well just go the full monty and replace evap as well.

Thanks in advance!


Edited: Sat August 15, 2015 at 8:51 PM by Drake57

bohica2xo on Sat August 15, 2015 9:06 PM User is offline

Um yeah...

2 blown compressors, filled the primary filter (condenser) and finally the secondary filter (orifice tube) with bit of compressor.

I am curious - if you never flushed the condenser, where was the lacquer thinner used?

At this point you have a completely contaminated system. Run with thinner, metal spread past the orifice tube in to the evaporator. HECAT will be the final word on whether or not you can flush the evaporator successfully - it is his specialty.

As for the process to R&R the evaporator on that car, your best bet is to buy a Mitchell or Alldata subscription for the car. You get the full factory service manual with all of the steps to do the evaporator (and every other task) on that car.

Wait for some answers before you go over a cliff on your own.

.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Jag987 on Sun August 16, 2015 1:56 AM User is offline

Yes, the evaporator can be flushed, and so can the condenser. But time is money, how long will it take to flush these and how much flush solvent will be required? Even with my Hecat pulsator, it is sometimes cheaper to replace the condenser than it is to flush it. The evaporator I would always try to flush unless it is cheap and has to be removed anyway to change the txv, but this one has an o-tube not a txv. The book shows about 6 hours to replace the evaporator.

As far as instructions, I have been having fairly good luck using workshop-manuals.com. It is free, not all years/models are listed, there is constant popups asking for donations, but it is fee and I have had fairly good luck with it.

Jag

-------------------------
I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

Drake57 on Sun August 16, 2015 12:42 PM User is offline

Drake57 on Sun August 16, 2015 12:42 PM User is offline

I did flush condenser and evaporator on first compressor replacement, replaced all o rings, o tube, accumulator. I don't remember what time of year it was, I just couldn't seem to evacuate all of the lacquer thinner. I will never again use LT for flush agent. On first replacement, there was no sign of contamination, the problem was that the OEM compressor leaked like a sieve.

I've already ordered condenser, and am wrestling with whether or not to replace evaporator. I'm just not sure I can get all particles from evaporator, and I really would like this repair to last.

Edited: Sun August 16, 2015 at 12:49 PM by Drake57

TRB on Sun August 16, 2015 1:00 PM User is offlineView users profile

If you left any lacquer thinner in the system. It broke down the oil and was most likely the cause of your repeated failures. Evap can be flushed, one important point is the type of equipment you use to flush the system. The cheap flush guns can work, but you have to make sure to remove all the debris and flush. The Hecat products work much better removing debris and flushing agents.

I've got your order on hold until you decide what you would like to do.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

bohica2xo on Sun August 16, 2015 2:52 PM User is offline

With all of the shared platforms in the automotive world, the price of new condensers has come way down. Under $100 condensers are common. It is not cost effective to flush them.

There is a big difference between flushing an evaporator and a condenser. At one time I worked for Dunham-Bush, and I have seen plenty of odd stuff come out of heat exchangers during an autopsy.

The condenser is subject to un-filtered debris at high velocities and pressures. This can jam big chunks in places they clog for good. A common thing in serpentine condensers. Multi-pass parallel condensers have a header chamber on each end of the tubes. Debris can stack up in the headers, and block the lower tubes. Back flushing may not remove these debris.

Evaporators operate at lower pressures, and are protected from large debris by either the orifice tube or the receiver & TXV. You have a much better chance of clearing most evaporators. A good thing too, given the large labor cost of replacing many evaporators in many cars. There are of course a few exceptions, with complicated distribution schemes - and I am sure Karl at HECAT can name most of those.

In the case of the Contour listed in this thread, there is a high probability that the evaporator can be flushed successfully in place with the right equipment and solvent.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Drake57 on Sun August 16, 2015 3:08 PM User is offline

I'm pretty discouraged at this point, each time I flush I get more glitter and a few black specks. If same thing happens during operation, it's bound to damage compressor again. I think it's time to replace both condenser and evaporator.

Thanks for the assistance.

HECAT on Sun August 16, 2015 6:08 PM User is offline

Sorry to be late to comment. Its not uncommon after multiple compressor failures for the substantial fines to accumulate in the evaporator.

Yes, it can be flushed out, but you must remove the orifice first (OT or TXV; you cannot push enough flush or get enough air volume thru it to blow dry)

If you keep seeing the "glitter" fines, you need to flush more. Better results in moving debris can be had, when you can push a lot of flush thru it. When clean it needs to be completely dried out well. Use filtered compressed air and blow, blow, blow, then blow some more.

If you are not confident in your flush method (flush chemical, delivery method, debris removal, and flush removal); replace it.

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HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 


Edited: Sun August 16, 2015 at 6:35 PM by HECAT

Drake57 on Mon August 17, 2015 8:40 AM User is offline

Thank you. Of course I have removed O tube, that was my first indication of trouble, it was heavily caked with fine silver particles.

I am flushing with paint thinner, using 1 quart flush gun, with dry filtered shop air. I really have no other choice, but after flushing 8 times, using 16 oz flush agent each flush, I still get some bright silver and a few black particles.

I'm just not sure I'll ever be able to flush it out. I think the work to replace evaporator is worth the peace of mind.

HECAT on Mon August 17, 2015 9:25 AM User is offline

"Paint thinner" is often comprised of a bunch of B grade solvents that cannot be sold as stand alone A grade solvents. Basically a cheaper solvent, which provides the solvent manufacturers with a path to market their lower quality (inferior) batches. The consistency and percentages of the given solvent components often varies greatly. So when considering this as a precision A/C flushing solvent; which component chemical has been chosen for its ability to effectively dissolve the synthetic refrigerant oil and its residues? How will each component chemical react with common metals and elastomers (aluminum, hoses, seals, etc.)? What is the boiling point of each component, and how will you assure it has all been removed? What effect will trace residue (assuming you can remove to that point) have on chemically altering or reducing the lubricity of the new refrigerant oil? You do not have to answer these questions. When I say you must be confident in the flush chemical chosen; it is important to know and understand before using; what you are going to use, why you are using it, and how you are going to properly remove it. So IMHO "paint thinner" is not a A/C flush.

In this case of substantial debris fines in the Evap (and solvent suitability aside); the 1 qt flush gun does not provide the volume, or produce the necessary velocity to remove all the debris. With each blast you churn it up, remove a little more; while the majority of the debris just drops inside again and again. Will it ever get it all? Not likely. When I say you must be confident in the delivery method; this inexpensive, old, and obsolete 1 qt flush gun method, produces little confidence.

You are obviously reaching the same conclusions. This works much better.

-------------------------



HECAT: www.hecatinc.com You support the Forum when you consider www.ackits.com for your a/c parts.

FLUSHING TECHNICAL PAPER vs2.pdf 


Edited: Tue August 18, 2015 at 1:15 PM by HECAT

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