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MarineGrunt
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May 27, 2013, 10:37 AM
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2005 GMC Envoy 4.2
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Hey.....just a quick question. When we bought our Envoy the a/c wasn't cold. I pulled a vacuum, added some dye, and 134. It's leaking from the rear evaporator. I didn't fix it last year because we we're leaving for Florida the next day. You can see the leak on the fitting from under the vehicle. What are the chances it's just the seal? I guess I could pull the trim off of the inside of the vehicle and see if I can see a leak from the evaporator itself. Is that what you would do?
It's a very slow leak. The a/c is still working now and I didn't add any since last year. It's not quite as cold as what it should be but it's still cold.
Thanks
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Hammer Time
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May 27, 2013, 10:45 AM
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Re: 2005 GMC Envoy 4.2
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Where exactly are you seeing the dye?
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MarineGrunt
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May 27, 2013, 11:15 AM
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Re: 2005 GMC Envoy 4.2
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If you're laying under the vehicle and looking up by the right rear tire you can see the dye where the dye on the fitting and around the line that runs from underneath the vehicle into the body. There's some foam that surrounds the line where it goes into the grove interior. It has dye on it too. I think if I pulled the trim on the inside I'd get a better idea. I can post a pic when I get home if that would help.
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Hammer Time
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May 27, 2013, 11:47 AM
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Re: 2005 GMC Envoy 4.2
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So, it is at the opening where the pipes enter the cabin. That means it can be anywhere above that point and you aren't going to know until you open up the unit and see where it originates. My money would be on the evaporator. It is highly unlikely for it to leak at the seal unless some repairs were done and the seal was damaged during assembly. Find the drain tube and see if you can detect any dye in the inside of the tube. That would seal the deal on evaporator/expansion valve.
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Tom Greenleaf
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May 27, 2013, 4:35 PM
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Re: 2005 GMC Envoy 4.2
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Not sure MG on this but have heard of similar set ups get the hose corroded right there or could rub where it enters vehicle. Maybe, maybe you could clean off area (should show some oiliness) and soapy water might show some slight "shaving" cream at the leak, wipe down and see again to pin point if that lucky.
I like the electronic sniffer to find leaks but each way has some downfalls to pinpoint the exact spot. My sniffer (those you can't rent IMO) doesn't behave if windy or when checking for friends in full biz my detector goes off a mile away because they just used a whole can of brake cleaner or something that sets those off too, -- Tom
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Hammer Time
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May 27, 2013, 4:43 PM
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Re: 2005 GMC Envoy 4.2
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I think even a sniffer would be inconclusive until he gains access to the evap and exp valve.
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MarineGrunt
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May 27, 2013, 8:23 PM
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Re: 2005 GMC Envoy 4.2
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Last summer I planned on ordering an evaporator when we got back from Florida. I just kind of assumed that was it. Since the air was working all of vacation, and the rest of the summer, I just let it go. I just got thinking about it today and wondered if it was possibly a seal.
Yeah, I don't think a sniffer would do much good in this situation. Like HT said, it could be running down through the opening from up above. Heck, it could be spewing out, hitting the inside of the trim cover, and running down to the opening.
The wife's last day of teaching for the year is Wednesday so I'll probably start tearing it apart later in the week. I'll let you know what I find.
Thanks
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Tom Greenleaf
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May 28, 2013, 12:29 AM
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Re: 2005 GMC Envoy 4.2
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HT & MG - leak finding can be a real pest even with any and all types of tricks to find them. Electronic sniffer can go off if a cow pharts in another state! Pretty much you aren't sure until you know you are close, wipe clean and about see the exact spot with bubbles hopefully.
Not sure MG - but a new evap may not fit so nicely as the one it came with - watch out for that with evaps and condensers. A couple NG out of the box really makes your day!
Just beware MG this crap too is touchy. No rubbing of lines. Tough call but if an alloy connection to be disconnected is at hand some plain act as welded and will break the next part creating a domino of parts. Use of things like PB can help but that mess confuses leak detection.
If this turns into a nightmare of gaining access and broken plastic housings hit me off web for some ideas,
T
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MarineGrunt
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May 28, 2013, 8:38 AM
Post #9 of 22
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Re: 2005 GMC Envoy 4.2
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Thanks Tom.....I'm thinking once I gain access I'll be able to see the source of the leak since I put dye in last summer. It's pretty much narrowed down to a one foot area. When I had a leak in the Venture a few years back I almost buckled and bought a leak detector since I was having trouble finding the leak. One of the reasons I was having trouble is because I wasn't looking at the condenser because I installed a brand new one about 9 months before that so figured that it couldn't be it. Sure enough, the new one sprung a leak.
Do you guys know anything about a refrigerant called Envirosafe? I guess the stuff has been used in other countries for years and is suppose to be colder than 134. You also only have to use 1/3 the amount of 134. I guess it's a mixture of butane and some other stuff so I would wonder if the flammability would be dangerous. I don't think it's a huge amount but still. But, since you only have to use 1/3 compared to 134, you're only looking at about 11 ounces or so. They're located locally for me so that's what has me asking about it. Seems like there are quite a few out there that have used it or a similar product and there hasn't been any issues. About every one says their air is colder.
I've got about everything needed for a/c work except a scale that will weigh the bigger cylinders. Well, I don't have a way to recover the old refrigerant. I've always used the cans and one of those small kitchen scales. I can get a 30lb cylinder of 134 locally for $79 so I bought a scale that will handle more weight off of ebay the other day. I didn't get one made for a/c work but found a postal scale that can handle up to 86lbs. It's accurate to .2 ounces. I got it for $11 plus $6 shipping. The cheapest a/c scale I could find was around $100 and that was used. A postal scale ought to work okay, right? What's so different about a scale made for a/c work?
Also, is there any way to make some sort of a recover system out of an empty cylinder or anything?
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Hammer Time
Ultimate Carjunky
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May 28, 2013, 9:07 AM
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Re: 2005 GMC Envoy 4.2
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Dangerous?????????
It's a mix of butane and propane. It will turn your car into a rolling bomb if the evaporator leaks inside the cabin.
You know butane, the stuff in cigarette lighters and propane, the stuff in your gas grill.
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Tom Greenleaf
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May 28, 2013, 9:26 AM
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I believe "Envirosafe" is just "Freeze 12" and has different charging procedures and can't help much with that. Also think it is the refrigerant used in some places. This was meant for 134a so I do suggest staying with it and since you know the exact weight AND have the scale to .02 which is fine that's what I'd do.
You can BTW run the little cans thru real gauges - just be sure to purge lines and always know "tare" weights with whatever is on the scale when in use so you know how much product is used - duh for you I would think.
Recovery with an empty say 30lb tank. It's been done (I haven't) with dry ice, water in a large bucket such that your tank is such low pressure you probably would get most of it out. AYOR - if you mess up and mix in air this project will go south, pressures can be all funky and PAG oils 'no-like' the moisture in the air as it absorbs it, then can become acidic - NG of course.
Equipment is pricey of course. You might do better to have a place just take the 134a out and let them have it and start new but re-vacuum again anyway! Make sure that holds. Don't fret too fast if your vacuum doesn't hold it can be connections or how you are hooked up messing up.
Watch out for some of the ports for 134a do leak some with caps off - shouldn't be hysterical but could get a bubble with spit actually (did I say that?)
Some cool procedures for charging is locked up in A/C section, worth the read or print it.
Know that almost everything wants the correct weight of charge AND no air. The old 5lb R-12 systems with sight glass could handle being off quite a bit, yours really can't or performance will be affected. Really avoid overcharge! Works compressor too hard and less cooling to none if off enough! Without equipment to measure it all out and right amount back in you can get in trouble. Had to say that for the record.
No rushing when down to charging the final amount. Make as sure as you can that it's right. You do want a running system to cool at least some fast so oil is moving.
See PM coming...... Tom
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Discretesignals
Ultimate Carjunky
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May 28, 2013, 5:48 PM
Post #12 of 22
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Re: 2005 GMC Envoy 4.2
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Envirosafe is not on the EPA accepted snap list, so beware.
http://www.epa.gov/...igerants/buying.html
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on May 28, 2013, 6:15 PM)
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Hammer Time
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May 28, 2013, 6:08 PM
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The chemical name for this stuff is HC-12a and it's illegal in the US in R12 systems but not R134A
HC-12a From Wikipedia, the free encyclopedia Jump to: navigation, search  This article is an orphan, as no other articles link to it. Please introduce links to this page from related articles; suggestions may be available. (February 2009)
HC-12a, also called ES-12a, OZ-12a, and Hydrocarbon Blend B, is a "drop-in" replacement refrigerant for Freon-12 and to a lesser extent, R-134a. HC-12a is a mixture of hydrocarbons, specifically propane (R-290) and isobutane (R-600a), and is therefore considered nearly non-ozone-depleting when compared to dichlorodifluoromethane (R-12, Freon-12) or 1,1,1,2-tetrafluoroethane (R-134a). The mixture can be used in refrigeration systems designed for R-12. HC-12a provides better cooling than an R-12 system retrofitted to R-134a, with much greater energy efficiency as well. Unlike R-134a, HC-12a is completely compatible with the hoses and oils used in R-12 systems, making the conversion much easier to accomplish. HC-12a is also patent-free due to its non-synthetic nature.
Because of its flammability, it is illegal to replace R-12 with HC-12a in the United States. It is not illegal to purchase HC-12a, or to use it in refrigeration systems that were not originally charged with R-12, except for in certain states that prohibit the use of flammable refrigerants in automobiles.[1]
Some advantages to using the HC-12a mixture over retrofitting to R-134a are cost and labor. Since HC-12a is a "drop-in" replacement, no seals need to be replaced and minimal effort has to be put in to changing the refrigeration system around. Disadvantages to using the HC-12a mixture in R-12 systems is that it is potentially dangerous and is illegal in the United States. The refrigerant used is propane and other hydrocarbons which are flammable. However, it should also be noted that R-134a (and other refrigerants) are just as flammable when mixed with refrigerant oil, yet the quantity of refrigerant and oil in a typical system is so low that the danger in any case is minimal.
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Discretesignals
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May 28, 2013, 6:25 PM
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Re: 2005 GMC Envoy 4.2
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You know they have some funky rules. You can use propane in a R-134A system, but not a R-12 system. As a professional you can't use any type of refrigerant that isn't on the SNAP accepted list because you'll violate the clean air act, etc. But the DIY can pump non approved refrigerants into their systems all they want and it is made available without licence, but you need a licence to go fishing.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on May 28, 2013, 8:22 PM)
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MarineGrunt
Enthusiast
May 28, 2013, 9:49 PM
Post #15 of 22
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Re: 2005 GMC Envoy 4.2
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So what they're pretty much advertising is it's okay to drive around in a rolling bomb only if it's safe for the environment?
I didn't know if there was just a trace of butane and not enough to be flammable or at least to cause any explosion if there was any kind of an impact. From the sounds of it the whole works is flammable.
I was just curious what you guys thought of it. Screw the EPA. If it's not carjunky approved it's not for me. I can pickup a 30 lb tank of 134 for $79 at Sam's Club. I think that's right around the same price as that Enviro-Bomb crap.
Don't you love the laws and regulations of our government. It's insane.
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Tom Greenleaf
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May 29, 2013, 3:32 AM
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$79 for a 30lb 134a bottle seems real good in season! Plenty of "urban lore" out there. Stuff that isn't what it claims to be at all on containers and so on. The isobutane @ some % is used to move oil in less than optimal condensable gasses. Yes, there are reports of explosions but not as many as other problems out there. Heck, CO2 was on the table for the next refrigerant, basically harmless but takes wild high pressures to condense so just a blow-out would knock a hood off or worse.
1993 was the switch year for refrigerants. That year could be either and for some the new vehicles just came thru as pre-retrofitted new probably to use up the stock of parts already made - who knows?
By your M.Y. is has been fully designed to work with 134a as best it can. Most do well IMO......... Tom
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MarineGrunt
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May 29, 2013, 6:40 AM
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Re: 2005 GMC Envoy 4.2
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The one I can get for $79 is produced by Johnsen's which is based out of Texas. I think I might call them though and make sure they produce it themselves and that it's not imported. Oreilly's sells a 30lb cylinder of Dupont for $139 which I would definitely feel safer going with. As long as a 30lb tank would last me that might be the way to go. I'd probably get around 12 charges out of that.
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Hammer Time
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May 29, 2013, 7:01 AM
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You do realize that doing that will eventually take out your compressor from lack of lubrication?
You need to add oil too when you recharge.
There is another option too. They make block off plugs to completely disconnect the rear AC
http://www.streetrodguys.com/...gory_id,45/Itemid,1/
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Tom Greenleaf
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May 29, 2013, 8:36 AM
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I'm for blocking off rears. Especially in mostly lower need climates. Remember, you are really only splitting the BTUs of the one compressor not really getting twice the cooling force but puts it back where it does have a hard time getting to.
Yes - it will get hotter in IL and here than some of the South but not all that long at least in MA. I know it's a bit hack but a 12V power port fan clipped to an overhead grab handle for the couple days of extremes would push the air inside around - I did that for defogging better for one vehicle and it worked.
The potential for corrosion (here we go again) for the lines to the rear in the rust belt areas is real. No doubt other places too.
That would all be different in need if frequently having a full vehicle load of passengers. Odd thought (it's me you know ) an average person is adding about 2,000 BTUs of heat just being there!
Tom
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