Automotive Air Conditioning Information Forum (Archives)

Provided by www.ACkits.com

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Why bother flushing?

maillemaker on Mon September 14, 2009 9:17 PM User is offline

Year: 1990
Make: Ford
Model: E350
Engine Size: 460
Refrigerant Type: R12
Country of Origin: United States

I have just purchased a 1990 Winnebago Warrior based on the Ford E350 chassis. The dash AC does not work. As it is an R12 system, I am contemplating converting it to an R134a system. The compressor cycles so I am assuming it is simply out of coolant.

Over the years, every single vehicle I have ever owned has required major air conditioning work. It always ends up costing $800+. For example, currently my 2003 Chrysler Town and Country has a leak, according to the dealer, and they want $650 to fix it.

I have decided that for all the money I am spending in repairs I can easily buy the tools to do the work myself. You can get a vacuum pump from Amazon.com for $100, and a set of gauges for $50.

After reading for the past few days on how to do this conversion, it seems the process, generally is:

1) reclaim old R12 refrigerant
2) flush system to remove old oils and debris
3) replace accumulator/drier
4) pull hard vacuum on system for some time (45 minutes to overnight depending on what you read)
5) add ester-based oil charge to system
6) add R134a charge

However, after reading the HECAT flushing instructions (FLUSHING TECHNICAL PAPER vs2.pdf), it appears that you must basically disassemble the system down to its components in order to flush them.

If I have to go to that much trouble, why not just replace the components with new ones? With the exception of the compressor, it looks like from the kit pricing on ACKITS.com that all of the parts to replace the entire system can be had for about $500.

So what's the deal?

Steve

TRB on Tue September 15, 2009 10:46 AM User is offlineView users profile

Harbor freight a/c tools are junk in my opinion a total waste of money. Some do take the R & R approach to a/c repair and it will work. If you have a failure which leaves debris you have to replace everything single major component or you will have a repeat failure which would not be covered as a warranty claim. Bottom line is you need a clean system for it to operate correctly. They don;t send out a new system from the factory with odd oil amounts or dirty oil with debris. So which ever way flush or replacement in my opinion the proper way to have working system is to have a clean system.

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

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

robs on Tue September 15, 2009 2:10 PM User is offlineView users profile

Steve-
I wish converting the system from R12 to 134a would be that easy, but doing a proper conversion also requires upgrading the condenser to a more efficient style ( parallel flow) and adding a high pressure cut off switch (if vehicle not equipped already) is a must to get the best performance. That also requires hoses to be rebuilt to accommodate the new o-ring style fittings on the condenser. Not to mention, also changing out the expansion device. So if it was up to me, i would leave the Winnebago R12 and see whats causing you to loose refrigerant, maybe a leak from sitting for a while. Now in regards to the Hecat Flushing equipment remark, you pretty much answered your own question. If you have spent quite a bit of money on the vehicles you have worked on by replacing the parts, don't you feel that the equipment would of paid itself and saved you money by now from all you've spent on swapping parts. Now if having to flush each component by its self is what you are most concerned with, aren't you still doing that when replacing the components? i mean you still have to flush the hoses, evap and etc., unless you are just swapping parts without doing any flushing and that is still not be the proper way and will void any warranty. If i were in your shoes, doing numerous of a/c jobs, i would invest in a great flushing machine like the PULSATOR KIT.

maillemaker on Tue September 15, 2009 9:19 PM User is offline

Hi Rob,

My concern is just what you said: If I basically have to remove every part from the vehicle in order to flush it properly, why not just replace the parts with new parts when they are so cheap?

Steve

iceman2555 on Tue September 15, 2009 9:37 PM User is offlineView users profile

As the modern AC system evolves into a totally replaceable system, this question is often raised. Changes in the flow characteristics of the modern condenser and evaporator have made 'flushing' almost a thing of the past. Without specialized equipment, ie HECAT, flush systems it is almost impossible to insure a complete clean out of the components. Thus,it seems justifiable to simply replace the required parts. This becomes a 'no brainier' for the DIYer, it is his cash and his labor. The professional technician is faced with the same concerns, however, he is also faced with a customer that desires..no demands...a fully functioning repaired system with a warranty...but does not wish to replace the needed parts. The other downside, is that the customer does not understand the changes in the systems that mandate this new repair procedure, and when faced with the estimate often accuses the 'tech' or 'service writer' of being a 'ripe off'.
The last few years we have seen major changes in the automotive AC system...many of these changes require parts replacements to successfully repair at failed system. Unfortunately, the industry, in many instances, has failed to keep up with these changes and has failed to seek the training necessary to keep abreast of these changes.

All to often, after numerous compressor replacements (on the same vehicle) the tech makes the decision to completely repair the system as necessary. Now the issue becomes...who is responsible for the increased charges. The 'tech' or shop often must absorb these charges. Had the repair been pre sold as required this would not be the case. Another issue that may be come evident, is that the 'tech' has now lost customer confidence......'perhaps, he does not know what he is doing....should these parts been replaced in the beginning ???'.....

Total system replacement is here for certain compressor failures on certain vehicle types. Is it becoming the 'norm'? It seems to be....more times than can be imagined. The expertise and equipment to facilitate a successful AC repair (compressor) is changing each year...unfortunately....too many are still in the 'I've been doing this 30 years and I know what I am doing!!!' syndrome. The days of installing a compressor, orifice tube, TXV, AD/RD, flush and charge are gradually becoming part of yesterday.

-------------------------
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 September 15, 2009 9:42 PM User is offline

You may have misread something in the Tech paper (thanks for reading). You do not need to remove the heat exchangers and lines to flush them clean. However, you will need to remove the components that are normally replaced, or cannot be flushed through (compressor, filter, orifice, etc). This opens up the system and provides the open points and clear paths to perform a separate condenser flush and evaporator flush which can include the lines that also need to cleaned and may assist in making the flush jobs easier. If you are going to reuse the compressor, it will at least need to be removed and oil flushed with the fresh oil (found on the procedure page).

I would pay close attention to Robs suggestions as you may just end up with a functioning but very underperforming system.

Flush (properly) or replace, is your choice; but there is clearly no other option.

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



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

FLUSHING TECHNICAL PAPER vs2.pdf 

iceman2555 on Wed September 16, 2009 11:44 AM User is offlineView users profile

On certain vehicle models the TXV is located within the plenum box, the evap/TXV assembly must be removed to facilitate proper flushing of the system. At this time one must decide the value of replacing the evap or not. Considering the mileage, labor to remove and replace once more, the possibility of a future (near) evap leak are decisions that must be made considering the replacement or reuse the old evap. Personally, servicing a vehicle with over 75k miles, with a failed compressor and the need to remove the evap to flush....a strong recommendation would be made to the customer to simply replace the components instead of 'flush and go'.
When the evap inlet and outlet are accessible from the engine compartment, of course, a flush (proper) would be the preferred method of repair.
One other major concern when servicing the system is to insure that the system is totally and properly recharged. Failure to completely recharge a system is a major cause of replacement compressor failures...both for the 'tech' and the 'DIYer'. The use of proper recharge equipment to measure the correct amount of refrigerant, and no the bath scales are not acceptable, should be the only acceptable method. Charging to pressures and the use of small cans or a single 30 lb cannister are not considered a valid recharge method.

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

TRB on Wed September 16, 2009 11:54 AM User is offlineView users profile

Iceman, were you going to have Kurt call me or am I supposed to call him? Sorry to hi-jack the thread but Ice is dropping the ball again!

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

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

iceman2555 on Wed September 16, 2009 2:52 PM User is offlineView users profile

Sorry, got busy on the phone last PM...will do right now......talking to him now.....or at least his voice mail......

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

TRB on Wed September 16, 2009 3:26 PM User is offlineView users profile

I got a hold of him but thanks for all the help.

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

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

HECAT on Wed September 16, 2009 10:49 PM User is offline

Quote
Originally posted by: iceman2555
On certain vehicle models the TXV is located within the plenum box, the evap/TXV assembly must be removed to facilitate proper flushing of the system.

I completely agree that the orifice (regardless of type) must be removed for effective solvent flushing to be performed on the evaporator. This is usually a fairly easy issue when it comes to an orifice tube system or when the txv is located in the engine compartment; and does not require evaporator removal to accomplish. Although a solvent could be pushed through the orifice, the necessary flow rate is compromised and you will never get enough dry air or nitrogen air flow through the orifice to effectively remove (evaporate) the solvent.

When the TXV is located in the passenger compartment, dash and or extensive interior removal becomes required. This can be done in a few hours in some models and up to 30 plus hours in some MB models and certain aircraft. I have always had the opinion that if I had to spend that much time and effort to access the evaporator, I would considered this to be a case for replacing the component.

However, I was asked by an OE to test flushing through the evaporator with a TXV installed to see if this could be accomplished without such extensive removal. Skeptical that it could be done, I agreed to perform the testing to produce confirming data that it could not be done. I had to reverse my stand and accept the successful results, that were also duplicated by the OE. I have since successfully repeated this process on aircraft (with that OE) and on a hybrid vehicle that was deliberately contaminated with the wrong (PAG) oils for this test.

It does require the use of our H1000 flusher and Genesolv SF (HFC-245fa). This refrigerant flush has a higher boiling point than 134a and does not gas after passing through the TXV, which allows for successful liquid flushing. This flusher then recovers (removes) the Genesolv SF with a vacuum recovery process. Yes it is a very expensive unit, but it has its place; and not all things we see as impossible, are so.




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


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

FLUSHING TECHNICAL PAPER vs2.pdf 

iceman2555 on Thu September 17, 2009 8:57 AM User is offlineView users profile

You and I have discussed this issue on several occasions, and it is agreed that with the PROPER equipment, this procedure can be accomplished.
However, it dealing with the every day AC shop and their repairs procedures, it becomes an almost mute issue. Heck, we are lucky to get them to flush the darn thing to begin with. Keeping in mind that app 25% of the repair facilities today lack the REQUIRED recovery machines. Flushing to most involves a can of BrakeClen and shop air...straight from the compressor...no filters...no driers....nope just the prospect of a possible oil/moisture laden air purge. But Hey, BC evaporates so fast...can not possible leave a residue?!!!
This year, in our training classes we are actually doing a section on "How to Flush". Can you believe it...but like most aspects of the repair of a modern AC system, things have changed. We see significant compressor failures that can be contributed directly to residual debris remaining in the system, not to mention the prospect of flushing a late model HE condenser with a simply blow thur cannister of 'what ever happens to be handy' flush.
Last week, received a call from a jobber wanted me to contact an installer concerning numerous compressor failures on same vehicle. During the conversation, discovered that the shop did have the required R/R machine, but did not use it....."can charge by pressures better.....seems as if I can make the car cooler this way" (not sure but I think that was a quote). Does flush, uses a popular flush chemical (TRB you know which one) but does not air purge......and replace a condenser..."why ? never had to do that before".
Ask several questions concerning the repair...one how much lube did you drain from the compressor.....'almost none ..maybe 1 oz.....and the complaint was a noisy compressor.
What color was the lube?.....Dark gray almost black. Does it have an odor? Yes, strong chemical odor....mmmmm...wonder could that be some residual flush....perhaps...maybe...yep..think so. That and the aspect of the darn thing was operating with a possible low refrigerant charge (charging to pressures..not specs). Keep in mind that this was the third compressor install after the initial OE unit failed....oh yes...it too was noisy.
One would think that this is an extreme case...but yet...seems like more and more of these events are occurring.
Should have stayed in Dental School....would be retired now...or at least working in an office with multiple very lovely female assistants .............but then.......wow!! What a dream!!!!

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

TXAB on Thu September 17, 2009 11:00 AM User is offline

Yeah, but would you really want to look at this at the office?



-------------------------
"Don't get stuck on stupid!"
---- Lt. Gen. Russel Honore

TRB on Thu September 17, 2009 11:03 AM User is offlineView users profile

My opinion if someone be it a professional mechanic or a DIY person is willing to short cut the flushing process they will be willing to short cut the R & R procedure. I know for a fact that many would not pull a dash to replace a evap core. Heck we have posts on this forum where people won't pull an evap case on a Toyota (very easy) because they feel it's to hard. Let alone pull a core on a Pontiac Solstice where the only thing left in the vehicle is the back seat. So what I'm getting at is people want an easy fix so it's an R & R process. But they fail to R & R every item so we have compressor failures. Then these same people want the vendors to warranty the compressor and other items as "compressor failed"! So where flushing does take time and the investment in tools. It also provides the ability to do the job correctly without having to pull the dash on many vehicles. So where does this leave us as sup[pliers in this industry? We need to have the jobs done correctly! People want to short cut the process and want the ability to make a claim at every failure be it legit or not? At some point we as suppliers can't afford to support people that fail to do a job correctly. But as we all know it a difficult position to be in when the customer has spent X amount on product and they believe they have a defective item, which is not always the case.

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

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

Back to Automotive Flushing Forum (Supported By Hecat Inc.)

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.