Filter-Driers

What does an filter-drier do?

The Filter-Drier is a canister typically mounted near the Condenser. The filter-drier receives the liquid refrigerant from the Condenser and has two primary functions in the air conditioning system:

1. To filter contaminants. (It is the primary location where larger contaminants will end up)
2. To remove moisture. (The desiccant stored inside the filter-drier removes any residual moisture from the system that evacuating doesn’t remove)

Removing moisture is the most important function, as moisture is the #1 enemy of the a/c system. Combined with refrigerant and lubrication, moisture will turn acidic (hydrochloric acid) and start to eat the system up from the inside out. It is necessary to replace or restore the filter-drier whenever the system is opened up to the atmosphere.

Some later model GM systems (most starting in 1973) use a VIR (Valve-In-Receiver), which is mounted on the Evaporator. This valve is a combination of the POA valve, drier, and expansion valve used in earlier systems. For information on VIR’s, click here.

Note - 1977 & later model GM systems use an Accumulator, instead of a Filter-Drier, to perform a similar function. An Accumulator is usually located immediately after the Evaporator’s suction outlet.

Buy a new filter-drier!

Classic Auto Air offers a number of new, replacement filter-driers, including:

For information on other replacement new, NOS & NORS Filter-Driers

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Can’t find a new filter-drier? We can restore your old one!

Because many filter-driers are no longer made, Classic Auto Air offers restoration services for your original.

Filter-Drier restoration service includes:

• Cut open and clean internally
• Replace filter and desiccant
• Reassemble and weld back together
• Pressure test and paint

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