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Shop starts retrofit to 134A but can I switch back to R12

KingRincon on Mon August 18, 2008 3:36 PM User is offlineView users profile

Year: 1992
Make: Toyota
Model: Paseo
Engine Size: 1.5L
Refrigerant Type: R12
Country of Origin: United States

I am new to this forum. I’ve decided to do some work to my A/C system myself to save money. This is a 1992 Toyota Paseo R12 system. Here is the history for this system. The system has had a small hole leak in the liquid line for several years. I just started driving the vehicle more frequently and decided I’d have some professionals check out the system and they diagnosed. Had an expert repair the hole.

Then have another shop tell me they can retrofit, evacuate and charge system all for $120. I’m excited and agree. The mechanic starts to retrofit then tells me the system will not take in more than 5-6 ounces of R134a and that an orifice tube or expansion valve is clogged and needs to be replaced. He also tries to upsell me on a new compressor. I decline his services and he tells me the retrofit is already complete. I really would like to make this simple and keep it as an R12 system. Hopefully I can just replace the drier which from reading here I think should be changed and then have it evacuated and charged with the R12.

How difficult is it to reverse what this mechanic did to keep my R12 system? He was only working on it for about 10 minutes and appears to have just put some sort of fittings onto the shrader valves. I have taken a photo of his work and will try to add to the post but can someone please explain procedure for adding photo to this post. All help and advice is greatly appreciated.

HECAT on Mon August 18, 2008 4:53 PM User is offline

..."The system has had a small hole leak in the liquid line for several years."

Does this mean it was constantly being topped off or inoperative for several years? If being topped, were the cans from the auto parts store with oil, sealer, dye, etc?

..."I’d have some professionals check out the system and they diagnosed."

These guys just found the leak?

..."Had an expert repair the hole."

This is somebody different who repaired the leak? Was it vacuumed and rechargrged? Was leak repair verified?

..."another shop tell me they can retrofit, evacuate and charge system all for $120. I’m excited and agree. The mechanic starts to retrofit then tells me the system will not take in more than 5-6 ounces of R134a and that an orifice tube or expansion valve is clogged and needs to be replaced. He also tries to upsell me on a new compressor. I decline his services and he tells me the retrofit is already complete."

Why did you decline?

..."I really would like to make this simple and keep it as an R12 system. Hopefully I can just replace the drier which from reading here I think should be changed and then have it evacuated and charged with the R12."

This may indeed still be possible.

..."How difficult is it to reverse what this mechanic did to keep my R12 system? He was only working on it for about 10 minutes and appears to have just put some sort of fittings onto the shrader valves."

Pictures of the adapters are not necessary. R-134a must be removed and conversion adapters.


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mk378 on Mon August 18, 2008 5:01 PM User is offline

If those are aluminum adapters, one short and one tall, you're probably dealing with the (fortunately incomplete) aftermath of the use of a death kit. I don't know if death kit "oil" can be trusted to not react with R-12. I think it is PAG based.

The new version of the death kit also has sealer in the cans of R-134a that you're supposed to charge with.

And you can put a full charge into a system with a blocked TXV (definitely you have a TXV system, not OT), it won't cool at all of course but it will be fully charged.

The accumulator drier MUST be changed and a vacuum pumped for at least a couple hours on any system that has been sitting for years with a hole in a line. If he only worked on it for 10 minutes I doubt that any evacuation at all was done.

Edited: Mon August 18, 2008 at 5:07 PM by mk378

KingRincon on Mon August 18, 2008 5:14 PM User is offlineView users profile

The system was inoperative for those several years while the hole in the liquid line was present.

The A/C professional who repaired the hole on liquid line said it held with a vacuum but he doesn't use R12 so he could charge.

I declined because he wanted more money to replace the TXV and possibly compressor. He was talking some outrageous coin to repair.

He removed the few ounces of R134a that he was able to charge because I declined the repairs and it was a free estimate. So he left the fittings in and claimed the retrofit was done. I don't believe he was a great A/C technician.

Could it really be possible that my system is "black deathed" because of what this guy did? The fittings look brass-copper in color.

I'd like to post photo here to get some advice. Please advise on how to attach photo to post. Thanks for your help...

neilh on Tue August 19, 2008 3:59 AM User is offline

sounds like all he did was add some conversion fittings: one on the hi side, one on the lo side..R12 is about $15-$20 per 12 ounce can (ebay) and the oil used is 525 viscosity mineral oil...you need to check NAPAs ac system capacity chart to find out exactly how much oil and how much R12 has to be added to fill up your ac system. new mineral oil and the R12 refridgerant charge must be as accurate as possible.. the best bet is to flush out all the oil in there now (blow out the condenser, blow out the evaporator, pull off the compressor and drain out all of the oil after dis-connecting the two lines, replace the accumulator and the orifice tube or TXV valve (whichever you have)....once its flushed before assembling everything add your oil (get a good factory service manual for your specific year and model to find out where and how much oil is added to each component)..its usually a couple ounces are injected into the evaporator, a couple ounces into the accumulator, a couple ounces into the condenser and the rest of the oil goes into the compressor..a cheap leak tester kit should have an oil injector or an oil syringe to shoot the oil into the incoming line(s)..once the correct oil charge is added (R12 uses mineral oil and R134A uses PAG oil. the two oils are not compatible with each other) you can then re-assemble everything. install the accumulator last..replace any o-rings wherever you disconnected lines .. use HBNR o-rings...next buy a vacuum pump (minimum for a decent 1.5 scfm pump is around $125) or take it to a shop to have them evacuate the sytem. if the vacuum holds for 10 minutes you should be good to charge with refridgerant. you need R12 or R134A gauges, charging adapters and a can tap

Edited: Tue August 19, 2008 at 4:06 AM by neilh

mk378 on Tue August 19, 2008 8:58 AM User is offline

Find out if the guy added or removed any oil. If not you still have a R-12 system; just unscrew the adapters and put shrader valve cores back in the stock ports if they were removed. Then you have to wonder if you have enough oil, the only way to be sure is to flush everything and put in new oil.

Pull vacuum for several hours to try and dry the system out. Then change the receiver-drier and evacuate again. Every R-12 system should be pressure tested with something other than R-12 to be absolutely sure it doesn't leak before charging with R-12.

Edited: Tue August 19, 2008 at 8:59 AM by mk378

HECAT on Tue August 19, 2008 9:18 AM User is offline

With the system being out of service and discharged for years, it is probably best to open up the system and do some investigation. This could be a truly challenging revival of a dead system requiring many steps to complete a proper repair that will perform. Taking short cuts usually just turns out to be expensive "I told you so" lessons and no cold air.

The compressor and other parts may have begun to corrode and this would all just cause a rapid failure if system is attempted to start. This may have already occurred as the tech tried to charge in R134a making him state the TXV is clogged and the compressor is bad. I would start with taking a look at the TXV and what is at the inlet (if anything). I would remove the belt and see what the compressor feels like when turning (grinding, catching, etc is not good). I would also take a look at the condenser inlet and even back blow some air through it to see what the oil at the inlet looks like and if it contains any metal debris.

Posting back what you find will give us a better picture of what you have (the condition of your system) and what steps will be required to get this system working again.






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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 

KingRincon on Tue August 19, 2008 10:10 AM User is offlineView users profile

Thanks for all the advice. Where can I get a good service manual that will also help detail the step by step procedures to the A/C system?

webbch on Tue August 19, 2008 10:28 AM User is offlineView users profile

As a fellow DIY'er , I'll just remind you that if you plan to do it ALL yourself, don't expect to save any money on your first or second repair. I finally consider myself reasonably well setup to do my own work on either R12 or R134a now that I have a recovery machine, vacuum pump, tanks, electronic scale, leak detector, adapters, gauges, etc., but with the money spent just on tools, I could easily have paid for 1-2 full system replacements done properly at an a/c shop......so don't plan on saving any money on the first couple of jobs if you go that route. If you plan to do everything EXCEPT recovery, vacuuming & recharging, you could probably save a few bucks, but then you have to bring it to shop to have them vaccum and charge it, and if there are problems, you have to go back to have it evacuated again.

If it were my system, I'd be terribly concerned about the quality of work that has already been done on/to it. From what you've described, you have created several major unknowns:
1) You don't know if sealers have been added
2) You don't know if incompatible oils have been used when they started the conversion to R134a
3) You don't know if the leak in the liquid line has been repaired adequately.

If fixing the leak required a new $120 line, I'd bite the bullet and go do a proper repair all the way through (new condenser, flush all the lines, flush the evaporator, flush the compressor with new oil, and put the system back to R12. It'd end up costing more that way, but anything else is just throwing good money after bad IMO.

mk378 on Tue August 19, 2008 10:40 AM User is offline

I agree with HECAT. Take a few things apart and look for water, rust, or metal particles in the lines. Do a basic compressor test where you hold your finger over the outlet and spin it by hand to see if it builds air pressure. If the system is majorly contaminated you may be better off to do a total replacement from the outset.

HECAT on Tue August 19, 2008 12:41 PM User is offline

Quote
Originally posted by: KingRincon
Thanks for all the advice. Where can I get a good service manual that will also help detail the step by step procedures to the A/C system?

here

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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 

Voyager97 on Mon October 20, 2008 6:14 PM User is offlineView users profile

If your 'mechanic' guy only spent 10 minutes on the job then all he could have done is fit the R12/R134a valve adapters.

He certainly did NOT evacuate the system,
or strip the system and flush the mineral oil out (mineral oil & PAG oil do not mix),
or change the old hoses for new barrier hoses (R134a has much smaller molecules and will seep out through standard hoses),
or change all the O rings for new HNBR O rings,
or replace the desiccant in the filter/drier,
or re-assemble the system then pull a deep vacuum to remove air & moisture.

In short - the guy was ripping you off $120 for a 'conversion' which is guaranteed to fail.







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Vic @ Pennine AutoChill

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