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Old 03-08-2003, 04:03 PM
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Join Date: Apr 2002
Location: RI
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A/C Leak Detection

I am planning to buy an A/C leak detection system/tool. Looking for recommendations as to which type to get, electronic or dye based. Will be used to detect R134A and R12 leaks in auto A/C systems. It will be used infrequently by a hobbyist, not a pro.

Thanks Much.
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Old 03-08-2003, 05:06 PM
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Join Date: Sep 1999
Location: Miami, FL
Posts: 645
These are rather expensive.

I have an R-12 detector made by Snap-On that I purchased 5 years ago for $60. Imagine my surprise to learn that the thing cost about fout times that new.

I think you need a separate tool for R-134. These come with a sniffer sample a small vial that can be used to test the device. When it senses R-12 or R-34 it beeps faster and faster.

I would try E-bay. Look for Freon Leak detector or just leak detector.

Good luck!
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Old 03-08-2003, 05:31 PM
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Location: Southern New Hampshire
Posts: 418
One of each...

I've discovered over time that you really need one of each if you want to cover all the bases...
The UV dye method is excellent where there are multiple possible sources of refrigerant... i.e. near the compressor... its hard to tell exactly which fitting or seal is leaking with a sniffer. Don't misunderstand, it can be done, but its a challenge. The dye will appear (glow) right at the source of the leak. The drawback of dye based systems is the initial insertion of the dye into the system. If you don't have the proper tools/manifold, you'll have to find a can of refrigerant that already contains the dye.
The sniffer is best when looking for an evaporator leak. By putting the sniffer "wand" into a dash vent, you can detect evap leaks that you could never see with dye.
My MAC sniffer will detect both R12 and R134a... I think most will.
You can easily find a good sniffer on eBay for less than 100 bucks if you're patient. You'll be amazed at how sensitive they are.
Dye is inexpensive but they charge outrageous prices for the UV lamp. Just go and buy a UV bulb (I've even seen them at Walmart) and put it in a drop light.
Hope this helps. KenP
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Old 03-08-2003, 06:57 PM
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Firstly, I wouldn't recommend buying a sniffer on ebay. The reason is that the sensor is ruined if it comes in contact with oil of any kind. This would seem to make this a risky proposition when buying one used and unseen.

The same reason keeps me from buying one, that and that fact that UV dye has worked so well for me. The UV dye is no problem for 134, it is readily available in a can about anywhere, just make sure you purchase it with the correct oil type, PAG or Ester.

I have an injector that uses a pure dye and is compatible with 134, 12 and any oil. It cost about $60 at my automotive a/c shop.

I have a UV lamp and yellow safety glasses and it has yet to fail for me in diagnosing leaks. Most leaks are in a place where you can see them and if it is the evaporator, you will see UV dye in the condensation water that drips underneath the car.

Personally the UV dye works for me far better than a sniffer.

My $0.02,
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Old 03-09-2003, 07:47 AM
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Location: Southern New Hampshire
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You're correct, but...

Larry is correct that sniffers can't tolerate contact with oil.. it contaminates the sensor module in the sniffer.
On the other hand, the manual on my MAC says the module goes bad all by itself over time ... and they recommend replacing it every year anyway. They come two to a pack and are inexpensive... takes about 60 seconds to change it. On my MAC, its mounted on the end of the "wand"... and there is a shield over it to keep it away from oil contact.
As far as eBay is concerned, I've found that most reputable eBay sellers will guarantee what you buy isn't DOA.. if you write and agree to that before your bid. Sniffers are a piece of electronics, so you need to agree to some sort of guarantee anyway before purchase. If the answer is no, buy it from someone else.
For fittings/seals under the hood, if you have a dye injector, UV works great. I've got specialized dyes (different colors) for refrigerant, motor oil, hydraulic oil, coolant, P/S fluid, etc... all different colors under UV light. I've found that UV dye is absolutely the best way to find a coolant leak... like those nasty ones that you can smell but can't find... once you have a UV light, the dyes are very inexpensive... and a little goes a long way.
Good luck. KenP
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