"Cheap" Harbor Freight elec refrigerant leak detector test - Page 2 - PeachParts Mercedes-Benz Forum

Demothen · #16 07-24-2016, 02:26 PM

No, I think the detector was kapuut. I swapped tips and it was still misbehaving. Swapped it out and the new one seems to indicate a sizable leak in the evap core, or it is possibly detecting the cleaning foam I flushed it with - though that was months ago. Going to try hosing the evaporator housing out later today and checking it tomorrow. If its still bad, I will be replacing the evaperator. No leaks were detected at the TXV, but if I stick the probe in a vent it detects something, even after blowing the core out with the hvac fan on and the AC off.
The good news is I am pretty well practiced at removing the dash now.

funola · #17 07-24-2016, 07:10 PM

Quote:

Originally Posted by ROLLGUY

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

Where was the leak on the Caravan?

ROLLGUY · #18 07-24-2016, 07:36 PM

Quote:

Originally Posted by funola

Where was the leak on the Caravan?

Condenser

funola · #19 07-24-2016, 08:09 PM

Quote:

Originally Posted by Demothen

No, I think the detector was kapuut. I swapped tips and it was still misbehaving. Swapped it out and the new one seems to indicate a sizable leak in the evap core, or it is possibly detecting the cleaning foam I flushed it with - though that was months ago. Going to try hosing the evaporator housing out later today and checking it tomorrow. If its still bad, I will be replacing the evaperator. No leaks were detected at the TXV, but if I stick the probe in a vent it detects something, even after blowing the core out with the hvac fan on and the AC off.
The good news is I am pretty well practiced at removing the dash now.

Did you read the instructions thoroughly? It is important you do. As far as I can tell, the 3 probe tips are identical. If I unscrew the tip while it's on, the unit triggers full bore. It seems the tip is an air gap ground for the sensor. I have not been able to determine what type of sensor it uses have you?

If I were you , before replacing the evap., I'd verify that it is indeed leaking with another method i.e. pressure test it with Nitrogen or air in isolation. Klima sells an after market evaporator for $347 as I recall. I spoke to them about it and he says the evaporator on a W123 seldom leaks. Let's hope yours is not the exception.

Demothen · #20 07-24-2016, 08:36 PM

See my recent post. Unfortunately the system failed spectacularly while I was testing again, but I did get a few more bleeps while I was pressure testing it.

funola · #21 07-24-2016, 08:42 PM

I guess you din't RTFM since it said specifically to shut the engine off when looking for leaks with the detector.

Sorry to hear the new R4 grenaded on you. What do you think caused it?

leathermang · #22 07-24-2016, 08:46 PM

Quote:

Originally Posted by funola

..... RTFM....

No Cursing.. this is a family oriented forum.... lol

Demothen · #23 07-24-2016, 08:55 PM

Actually, I did RTFM. I was getting detector signal with the compressor off and the fan off as well. Also after running the fan, waiting 10 minutes, then checking again. At this point I suspected I might be dealing with residuals from the fin cleaner I used, so I decided to test it with the car having sat for a while, then running the system and was about ready to shut the car off and see if I had a higher signal immediately after shutdown to indicate that it was refrigerant not residual cleaner. Unfortunately that was interrupted by the failure.

Sometimes you have to create alternative tests to try to reduce variables. More information is always valuable.

I havent gotten the system apart to check yet. I am curious if one of the bolts that was holding the compressor together sheared. Will probably be a bit before I start breaking the system down again. Still letting the oil drain and will want to degrease and wash everything really well before I start messing with it much.

funola · #24 07-24-2016, 08:59 PM

This pic was taken in the morning when it cooled off to around 78F and the pressure dropped to 0.958 MPa (138.9 psi). As the temps climbed it went past the 1.014 MPa and then drops in the evening. This sensor does not leak! It has hysteresis adjustments and an open collector output that can set off an alarm.

ykobayashi · #25 07-26-2016, 12:56 AM

I tried that one on my 240d. It worked. I waved the wand all over the engine compartment and it didn't beep. Then I got to the window and it started making noise. Then u stuck it in my dash vents and it started wailing! So uh yeah it worked. Kinda. I got rid of the car after that...family couldn't ride without AC.

nhatnguyen123 · #26 07-26-2016, 01:55 AM

funola · #27 07-26-2016, 08:18 AM

Quote:

Originally Posted by Demothen

Actually, I did RTFM. I was getting detector signal with the compressor off and the fan off as well. Also after running the fan, waiting 10 minutes, then checking again. At this point I suspected I might be dealing with residuals from the fin cleaner I used, so I decided to test it with the car having sat for a while, then running the system and was about ready to shut the car off and see if I had a higher signal immediately after shutdown to indicate that it was refrigerant not residual cleaner. Unfortunately that was interrupted by the failure.

Sometimes you have to create alternative tests to try to reduce variables. More information is always valuable.

I havent gotten the system apart to check yet. I am curious if one of the bolts that was holding the compressor together sheared. Will probably be a bit before I start breaking the system down again. Still letting the oil drain and will want to degrease and wash everything really well before I start messing with it much.

Before tearing the system apart, may I suggest evacuating the system of refrigerant and use the detector in the vent again to see if it was picking up 134a or something else previously. Probably the easiest way to seal the blown R4 o-ring is degrease the area and put duct tape around it.

Demothen · #28 07-26-2016, 08:26 AM

The system self evacuated. Very rapidly when the compressor split.
I will check the vents again though to see if the detector goes off.
I may end up pulling the evap to thoroughly clean the fins though

funola · #29 07-26-2016, 08:31 AM

Refrigerants are heavier than air, some can hang around for a while in enclosed spaces.

Demothen · #30 07-26-2016, 08:46 AM

I will keep that in mind, thanks.