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Eric, Automotive Repair Shop Manager
Category: Dodge
Satisfied Customers: 31915
Experience:  20+ yrs. experience as repair shop manager and technician.
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Dodge ram 3500: cooling when the compressor..high pressure

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Dodge ram 3500 diesel ...a/c problem
Compressor was replaced by shop near me .....a few days later the seal on the rear of the compressor leaked all refridgerant and of corse no cooling
when the compressor was replaced the drier was changed out , system flushed etcand a new orifice was installed this poss, just a o ring failure or too high pressure by the compressor ???



If it is the rear seal on the compressor itself that is leaking, then it is just due to defective seal. The compressor has a high pressure relief valve that blows out refrigerent if the head pressure is too high, either because of overcharge or restriction in the system.


This should be covered by the shop's parts and labor warranty and compressor replaced free of charge, unless you provided the parts. Then they will charge you labor to remove it and to install a new one after you go exhange it from wherever you bought it.

Customer: replied 6 years ago.

HI Eric

thanks for prompt would I be able to check if there is a restriction in the system ?

the shop that did this has been "running "me around for a week or more and I cannot get a definate answer , I do not clearly want to let them go ahead and fix whatever and not be happy or to have the vehicle breakdown again .........nor to be paying out for more parts.

I am not trying to put you in the middle by the way , i just want some advice as to the cause of the problem



The way to check for a restriction in the system is to first make sure refrigerent is full, and then use a full set of gauges(both high and low pressure hoses) to read the pressures.


High low pressure reading with normal high pressure reading is an expansion valve/orific tube restriction


normal low pressure with high high pressure reading is restriction in the condensor.


An alternative way to check only for restriction in the condensor is to use a water hose to soak the condensor in front of the radiator and while the engine is idling with ac on. If temperature at the vents drops by several degrees, then condensor has a restriction.


You generally will know if the loss of refrigerent is from the high pressure relief valve blowing off refrigerent because it is a super loud noise that can be heard over the sound of the radio or exhaust. And It only occurs when ac is running, so you would have been in the vehicle and heard it blow off the refrigerent.

Customer: replied 6 years ago.

thanks for info ......would the evaporator have a problem.........blocked or partially blocked ??




The only time in my life that I have seen a restriction or partial restriction in the evaporator is when stop leak products have been used in an ac system. Otherwise i have never encountered a restricted evaporator core as either the expansion valve or the orifice tube catches any debris and prevents it from entering the evaporator.

Customer: replied 6 years ago.

since i have not had the truck from new added products are unknown to me

The oriface tube was dirty when it was replaced but the compressor the mech. told me was ....tore up .

where is the expansion valve located ?? will it be advisable to put in a new one as well as compressor oil before replacing the seals at the rear of compressor ?



The orifice tube and expansion valve perform the same function and the vehicle has one or the other, but not both. The orifice tube would have been clogged with the stop leak, and they would have noticed that the evaporator wouldnt flush if it were clogged, so based upon that, I dont believe that is an issue.


If you paid for a compressor and were charged for a compressor, they should replace the compressor instead of replacing the rear seal, also it is quicker to replace the compressor than it is to rebuild that one.


The compressor oil will be replaced when this is done, because whether they replace the compressor or rebuild it, the compressor oil is lost when the compressor is removed from the vehicle.


No reason to replace the new orifice tube with a new one if it is only a few days or weeks old, although I would pull it just to verify that there is no debris accumulation.



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