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Dakotadrew
Dodge Dakota
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7/08/2004
16:10:31
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 Subject: A/C Overcharge!!!
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Over the weekend i was putting a can of 134a into my 99 dak. I have had a slow leak in the system somewhere but i didn't want to spend the money to get it fixed as i will be trading it in soon on a new one. Its a lot cheaper to put a can or two of refridgerant into the system to last the summer instead of putting the hundreds into the AC to get it fixed.
Well i had almost no cold air what so ever coming out the vents so i picked up a new can and also a can of AC sealer/detector. I figured what the heck, maybe it would fix the leak. Well i put the full can in and then the sealer but i had turned the can upside down to get it into the system a little quicker (as i had before with no problem). When i got both cans in, I checked the air coming from the vents and they were ice cold (of course). When i went to close the hood, I HEARD THIS LOUD ASS EXPLOSION FROM UNDER THE HOOD AND REFRIDERANT WAS COMING OUT FROM UNDER THE HOOD!. Nothing was left under the hood so i dont know if the vibration of closing the hood or what caused something in the AC system to burst. When i opened it up i say where that red leak detector stuff up around the high pressure point on the AC line (front left in front of the air filter) and then some more down behind the filter up against the cab??? Does anyone know what exactly burst? Are there seals that can burst from too much pressure? Or did it crack the lines, but i cant see any visible cracks? Any help here guys.
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Lab Rat
GenIII
7/08/2004
17:08:30
|  RE: A/C Overcharge!!!
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You most likely caused the PRV to release as it's designed to do. If you're lucky, the valve resealed properly and won't continue to leak.
I never use those system sealers, they are terrible for compressors and can actually cause failures by clogging small lubrication passages.
You still need to remove the excess charge in the system or it may pop again.
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Dakotadrew
Dodge Dakota
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7/08/2004
18:53:29
| RE: A/C Overcharge!!!
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So if that is the case, does that valve release in two different places??? As i said i saw two different areas where the dye from that sealant sprayed out of. Where is that PRV release supposed to be located??? Where at under the hood?
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Lab Rat
GenIII
7/08/2004
19:03:16
| RE: A/C Overcharge!!!
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No, but obviously it was running when it happened and I'm imagining that the engine fan is responsible for blowing it around.
The PRV is in the cylinder head at the rear of the compressor. Silver in color and has about a 14mm hex on it. You should see a large deposit of dye right behind it.
Can you tell if there is any pressure in the system at all? Is the compressor still operating? Any cooling?
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Dakotadrew
Dodge Dakota
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7/08/2004
19:09:15
| RE: A/C Overcharge!!!
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No, not a bit of cooling. About 10 seconds after the thing blew i went to shut off the truck and nothing but hot air was coming out the vents. I understand that the fan could have blown around some of that dye but i am just concerned on the location. The dye was only found in the front right corner right in front of the air filter box. Then there was also another descent area of the dye straight back on the left back corner. I was just concerned that i may have cracked the aluminum hoses that carry the refridgerant. Is that possible? If the fan did spray it around, wouldn't you think that there should be that dye all over under the hood? That is why i am just not sure what it did?
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Dakotadrew
Dodge Dakota
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7/08/2004
19:11:13
| RE: A/C Overcharge!!!
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SCRATCH THAT...I mean the FRONT LEFT and BACK LEFT corners.
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Lab Rat
GenIII
7/08/2004
19:51:02
| RE: A/C Overcharge!!!
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Not good, you must have had so much refigerant in it that you actually did blow a line or at least caused a joint to separate before the PRV could release enough to prevent it. The lines in and out of the condenser are located in front of the air filter housing. If you're lucky, the spring lock joints that connect the tubes came apart (sidenote: these fittings are notorious for leaking, probably where your problems started).
The connections are the weak point. If you see where they have come apart, you'll probably have to replace the garter springs and for sure the o-rings. Pep Boys has them, not sure about A/Zone.
It might be best to just take it to a pro at this point-but if you can patch it up yourself with confidence it will save some money.
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Bob Lincoln
Dodge Dakota
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7/08/2004
22:10:30
| RE: A/C Overcharge!!!
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Two mistakes:
1) Not having gauges on both high and low sides while filling.
2) Adding (liquid) refrigerant by inverting the can. It slams the compressor and can damage the vanes.
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Lab Rat
GenIII
7/08/2004
22:16:09
| RE: A/C Overcharge!!!
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Bob, yes you are correct but Sanden compressors are very durable when it comes to liquid slugging.
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Dean
Dodge Dakota
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7/09/2004
00:19:27
| RE: A/C Overcharge!!!
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It was probably the fact that he got liquid in the compressor along with the "stop leak" that caused the blow as much as anything else. If the system was really low then one can shouldn't have caused a blowout. It also shouldn't have emptied the system. I doubt it would have caused two leaks at once, but anything's possible.
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Dakotadrew
Dodge Dakota
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7/09/2004
15:55:01
| RE: A/C Overcharge!!!
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I know that the system was really low, because it wasnt' blowing out one single ouce of cold or even cool air. That is the reason i put the can of refridgerant in. Also the can of sealant said to put the sealant into a full AC system and if it wasn't full to put a can of 134a in before the sealant. Which i did. Dont know why the thing blew like it did???
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Bob Lincoln
Dodge Dakota
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7/09/2004
18:59:44
| RE: A/C Overcharge!!!
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"I know that the system was really low, because it wasnt' blowing out one single ouce of cold or even cool air."
Probably, but you don't KNOW that without gauges. A clogged expansion valve or drier/receiver could produce the same symptoms in a full system, and you could have overpressurized it. Been there, done that.
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Dakotadrew
Dodge Dakota
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7/09/2004
19:17:42
| RE: A/C Overcharge!!!
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Ok then i have another question for you. You know the high pressure point in the front left corner of the truck, well from there you can follow the alluminum hose down front of the truck and into the radiatior. Along this line directly behind the bracket that holds the bumper on there is a crimp in the alluminum line. Its a pretty descent crimp in the line that i got when i had my accident a few weeks ago when the bumper was pushed back into my radiator and had to of pinched the hose. Could this have created a problem with pressure???
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GraphiteDak
GenIII
7/09/2004
21:37:11
| RE: A/C Overcharge!!!
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That would be your condenser line to or from the condenser, but either way it was a RESTRICTION in your HIGH SIDE which is BAD.
If it was AFTER the condesner not so bad. The liquid would have stacked up in the condenser (not such a bad thing) and if the low side has a cut out the compressor would have shut off when it pumped down. But, when you added refer (into the low side) it would close the pressure cut out and let your compressor run, stacking MORE refer into the condenser. If that crimped line is on the GAS line going to the condenser, it would cause VERY high pressure with no where to stack the refer. Not good.
Your system probably saw 500PSI or something when you added refer.
And I agree, that dye sh*t is NASTY for compressor valves. I ONLY use it if my electronic leak checker wont pick up anything. Then wheather I find a leak or don't with the dye I pull the charge after a few days and pull a deep vacuum and recharge to specs with ONLY refer with NO dye/additives, etc.
You better get some gauges to see where you are at. They cost about $100 or so for a good pair like mine. If you have NO charge it most likely blew a hose/fitting.
I've never had any problems (yet) with the A/C on my Dak. I don't even know if it has a low pressure cut out, etc. I'll have to go look next time I pop the hood. Should be next to the accumulator.
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Bob Lincoln
Dodge Dakota
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7/09/2004
22:19:20
| RE: A/C Overcharge!!!
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Ya know, not to slam you, but if you had mentioned the accident and damage in your first post, and before you added freon, probably you would have been able to have the line fixed and then recharge it without popping the relief valve and causing all kinds of grief to the system. Most definitely that's why you had no cold air, and why the system blew. Please give as much info as you can when you first post a problem, and we can all help each other better. This was vital info to leave out.
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Lab Rat
GenIII
7/09/2004
22:53:38
| RE: A/C Overcharge!!!
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Bob, good point and I agree. That is critical information.
Graphite, any blockage on the high side is bad and very detrimental. If the crimp in the line was downstream of the orifice tube, it might have been different, IMO.
Wally
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GraphiteDak
GenIII
7/12/2004
02:15:09
| RE: A/C Overcharge!!!
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Lab Rat of course any blockage is bad.
But a blockage BEFORE the condenser I would have to say is much WORSE than a blockage after the condenser.
You can pump ALL of the refer into the condenser via shutting off the line AFTER the condenser. It will be in liquid form. Since it is no longer picking up heat via blowing warm air across the evaporator the pressure would even maybe stabalize somewhat reasonable in the condenser.
Running it a LONG time that way would of course be bad anyway. Without cool refer coming back to the compressor it would run HOT.
I bet he over charged it or the line was crimped going TO the condenser from the comp.
Which reminds me something. I remember the older FORD expansion valves, like used on early 80's fox body mustangs and similar, had a bad thing about sticking CLOSED especially after service where you vacuumed the system, etc.
Those units would basically run for quite a while without blowing any hoses. Actually, now that I remember it happened to my Mustang and the restriction was somewhere in that BLOCK thing Ford used just at the firewall where it connected to and from the evap coil. It restricted coming FROM the evap to the compressor which is very odd. I forget what the part was, or did. But it was such a restriction that the suction line froze BAD all the way to the compressor from the evap. Since the restriction was AFTER the evap it basically didn't drop any pressure at the metering device going TO the evap so the evap coil most likely had all liquid in it (nothing flashing to a gas) and didn't cool one bit in the car. This was about 10 yrs ago, but I remember one guy taking that block containing the expansion valve and other parts off and removing some part and putting it back on and it worked normally again every time! We fixed mine. That was when R12 required a license, but was still on the shelves!
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