GM 19256743
Evaporator Core

The first step to replace the Evaporator core involves identifying it through the combination of attachments used for the Evaporator outlet hose and the liquid line at the thermal expansion valve (TXV) that uses nuts for securement. The first step includes removing the hvac module together with the Evaporator case assembly. Begin by unscrewing txv bolts on the backing plate and afterward remove txv and backing plate through Evaporator pipes. Protect the Evaporator pipes by installing protective caps after you remove the o-rings from their position. Begin the next step by removing the dash seal of the hvac module front along with its screw that holds the Evaporator pipe cover in the blower case assembly before removing the coverage. A solution of soap and water applied to the core seal perimeter helps making the blower case assembly removal possible. To install the Evaporator core properly apply the required dosage of polyalkylene glycol oil then double-check that the seal rests in its appropriate position. The installation process requires the application of soap and water solution on the core seal and then insertion into the blower case assembly with the addition of the Evaporator pipe cover and its screw reaching 1 n.m (9 lb in) torque. Before installation of the hvac module front of dash seal initiate removal of protective caps from Evaporator pipes while inspecting that all seal contact surfaces remain clean and dry and free of lint. Only r-12 refrigerant oil (mineral) serves as lubrication during new o-ring installation on Evaporator pipes because mineral products delay pipeline corrosion. A dry-air method should be used to evaporate non-petroleum based solvents from sealing surfaces of the refrigerant system before cleaning surfaces to avoid solvent entry. Fix the txv and backing plate onto Evaporator pipes while tightening its screws on the backing plate to 9 n.m (80 lb in) torque level before installing the Evaporator case assembly and hvac module.

Install the TXV and backing plate to the evaporator pipes, secure the TXV screws to the backing plate at 8 N.m (71 lb in), then reinstall the evaporator case assembly and the HVAC module.

Detach the HVAC module front of dash seal and unscrew the two halves of the blower case assembly, separating them to extract the evaporator core from the blower case assembly.

First, remove the HVAC module and the evaporator case assembly.