Our latest featured service is A/C Evaporator replacement on a 1998 Dodge Ram 2500 Pickup truck; brought to us by a client from Yaletown, Vancouver.
A/C system failures usually fall into one of three camps: electrical, mechanical or leaks. The latter is by far the most common. On a vehicle air conditioning system there are many places to leak: numerous seals where hoses connect components; the hoses themselves; the condenser which is located in front of the radiator; the compressor, a belt driven unit mounted on the engine; the accumulator or dryer; and finally the evaporator.
The evaporator is the unit in the A/C system that delivers the cold air inside your cabin. It is among the most expensive parts to replace during an air conditioning repair due to its location: buried under the dash and inside the A/C /heater box. It is also difficult to leak test due to its hidden location.
Diagnosing an automotive air conditioning concern is a systematic procedure. First tests are to determine whether the electrical side is functioning correctly and second is to determine whether there is refrigerant in the system.
If there is little or no refrigerant there is a leak. Several methods of leak detection can be used and we usually employ them all. First is a visual inspection. Second is to add nitrogen gas under high pressure. Third is to add UV dye, partially charge the system and run it until a leak is found. A leak may be apparent after 5 minutes or may take several months (which of course requires an inspection after the car has been driven for a while). Fourth is to utilize an electronic leak detector, a sort of ‘refrigerant sniffer.’
Our featured Dodge truck required several methods. UV dye was already installed and we found very small leaks at the condenser and the hose seals to the compressor. We filled the system with nitrogen gas and that’s where we discovered a big leak: there was a large hiss coming from the evaporator core and pressure was dropping rapidly.
Most evaporator leaks are not this easy to find. They usually seep a tiny amount of refrigerant in their hidden chamber, out of sight and detection. The large, obvious leak on this 1998 Dodge Ram was most fortunate from a diagnostic perspective.
Repairs involved replacing the evaporator, condenser and hose seals at the compressor. We also replaced the accumulator as it functions as a filter for the A/C system and should be done anytime a leak of this magnitude is present.
Interesting, this truck had 350,000 kilometers on the clock and was in exceptionally good condition. It stands as a testament to the longevity of a well maintained vehicle.
For more about A/C system operation click this link http://auto.howstuffworks.com/automotive-air-conditioning1.htm
For more about the Dodge Ram pickup click on this link http://en.wikipedia.org/wiki/Dodge_Ram
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