Anticipating that I may convert my 85 300D back to R12 (had R134a, then Envirosafe ES12a, and currently R152a in it) , I am collecting /making tools needed to do the job successfully. This is a great opportunity for me to get hands on experience on AC work. I was curious about electronic leak detectors but do not want to spend a few hundred bucks or more on a name brand unit. When I saw this HF unit Electronic Freon and Halogen Leak Detector on sale, comes to just under $60 with 20% off coupon, I gave it a try. Hey if it false alarms, I have 90 days to return it and get a full refund.

Here are 2 videos. The bottle was totally dry when I vented what was trapped in the high pressure hose of the manifold gauge set after taking a pressure reading of the R152a. First video is just opening the cap slightly. Second video is puncturing the bottle with an awl simulating a slow leak. As you can see, it was able to detect R152a with no false alarm. This HF 92514 detector works with refrigerants which contain chlorine and fluorine such as R134A, R12 and R22. R152a is Difluoroethane which contains Fluorine which this HF detector will detect. It is legal and cheap as a tracer gas (3 cans for $11 at Walmart), unlike R22. I have a 30 lb jug of R12 which I'll vent some into a bottle and repeat the test.

https://www.youtube.com/watch?v=lHcqFJw5txY

https://www.youtube.com/watch?v=9Wmj7sd7i34

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

This pic is a leak test of my cheap digital pressure test set (all brass fittings are under water). The gauge is $10 shipped from Banggoods.com. I happen to have all the fittings already, otherwise it would be cheaper to buy an AC ball valve. I didn't want to use the manifold gauge set for pressure testing because there are too many connections which may be potential leak points plus the gauges are Bourdon tube, not digital, which makes it difficult to see minute changes in psi.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thanks for sharing funola might have to pick one of those up myself.

So how will that gauge setup work? I assume you will be pressurizing through the valve, then shutting the valve with the gauge still pressurized? How are you getting this connected to the car? Through a low side adapter?
I wonder how much noise will be in the "signal" due to outside pressure and temperature changes. I would assume that gauge compares internal pressure to atmospheric pressure, not to a vacuum?
Looks really good though. Let us know how it works!

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'85 300D - federal spec, built in late 84. 85 300D Complete AC System Rebuild

The gauge reads in PSIG units, what else would one expect for $10? I have bad news. Overnight the reading dropped to 40 psi. There were no bubbles that I observed so I am suspecting the gauge is leaking internally. It has a Silicon pressure sensor and I suspect internally it is poorly constructed and is leaking. I have swapped it out to a Bourdon tube mechanical gauge and repeating the underwater test.

Yes it is sensitive to temperature and atmospheric changes so you have to be mindful and that and also record ambient temps and pressures. I also tried compressed air from my 120V oil less compressor which has not been drained in a long time. It is probably full of water and when I let out the pressure with the ball valve, I can see visible water mist. With such wet air, I can see a 2 to 3 psi rise if I put the test set in the sun. With dry Argon, it does not rise or rise maybe 0.5 psi per the gauge.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Electronic refrigerant leak detectors are junk IMHO. We haven't used one here at the dealership in over twenty years. UV dye is the way to go............

Why do you think that? Just curios. This is my first experience an electronic detector and I have not seen false alarms yet. I have a very slow leak at the ferrule crimp in one of my manifold gauge set. I will hook it up to the car's AC and see if the HF detector can pick it up.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I have been helping out the last few Fridays at my local radiator shop, as they have been very busy. I worked on a Dodge Caravan that leaked the complete charge out in a week, and they could not find the leak with the dye. I used the electronic leak detector and found the leak right away. Even soap bubbles revealed no leaks. I do employ all three methods, but this is one time that two of them did not produce any results.....Rich

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All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

I wanted to see how sensitive the HF detector is and rigged up a test and made 2 videos. I had a hose with a plug on the end, cracked ever so slightly to let a few tiny bubbles/ second out seen in water. Anyone have any idea how slow this leak is, as in how long will it take to empty the system?

Hose in this video https://www.youtube.com/watch?v=rkxxSvGTDvA is connected to the low side port static pressure R152a Difluoroethane. The HF detector was able to detect it reliably w/o false alarm although the pickup has to be placed very close to the leak point.

Hose in this video https://www.youtube.com/watch?v=XygusUSjiJY was connected to a 30 lb jug of R12. The bubbles are fewer than in the last video but the HF detector still was able to detect it w/o false alarm.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

The Banggood digital pressure gauge is definitely leaking. This mechanical gauge has held pressure (and not drop a lot of psi's) for more than 24 hours now with just changes due to atmospheric temp and pressure. It moved not more than +/- 1 tick which is 20 psi. I would still like a digital pressure gauge to discern down to 1 or 2 psi so have ordered this one SMC ISE30A N01 P Digital Pressure Switch New Out of A Box | eBay , which I hope will hold pressure. I think it will. I wrote Banggood regarding their leaky pressure gauge, sent then pic of the test setup and they wrote back saying they will refund my money within 72 hours. Haven't gotten the funds yet but will see.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Got my $10 paypal refund from Banggood. I am impressed! The digital gauge arrived and is being tested for leaks. Hopefully this one will not leak.
The reading is in MPa, 1.014 MPa = 147.068 psi

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

How does that work for leaks in the evaporator ?
My first MB Diesel was an 81 Wagon.. it had a leak in the big line across the top of the engine AND one in the evaporator... when the electronic tester was put into the center vent it went off like a fire alarm..
I could have afforded to fix the big line ... but not the evaporator...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I bought one of those detectors from HF while I was in USA. This because of A/C problems on our W210. Also bought one of their gauge sets. Both still brand new in box! Evaporator developed a LARGE leak. Repair would cost a lot more than car is worth, so now just wind windows down

Maybe I should try and sell them up here.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Hmm. Just bought this detector. It seemed to work for a while, then I found a potential leak in the evap. I ran the fan for a while, then shut it off and checked again. Now the detector is going off with the lights flashing red & green as soon as i turn it on. May make a trip back to HF to swap it out.
NOT looking forward to swapping the evap out

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'85 300D - federal spec, built in late 84. 85 300D Complete AC System Rebuild

Maybe some refrig is trapped in the wand setting it off? Keep water out of the sensor which could damage it.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked