Download 1991 Chevy G 20 Van Primary (Front) Heater Core Replacement – Remove or Disconnect (Figures 5 through 10 and Figure 20) 1. Battery ground cable. 2. Coolant recovery tank. 3. Heater core hoses (140 and 141) (figures 6, 7, 8 and 20). ^ Place a clean pan under the vehicle to catch any coolant spillage. ^ Plug the hoses. ^ Allow coolant in the core to drain into the pan. 4. Heater distributor duct (134) (figure 9). ^ Remove the screws that hold the distributor duct to the distributor case and the distributor duct to the engine cover. 5. Engine housing cover. Refer to Access Cover, Engine. See: Body and Frame 6. Instrument panel. See: Instrument Panel, Gauges and Warning Indicators 7. Lower the steering column. Refer to Steering Column. See: Steering and Suspension/Steering ^ Raise and support the right side of the instrument panel. 8. Defroster duct (130) to distributor case (124) attaching screws. 9. Distributor to heater case screws. 10. Temperature door cable (145) (figure 10). ^ Fold the cable back for access. 11. Heater case (124) and core (122). ^ Three nuts at the engine compartment side of the distributor case and one screw on the passenger side. ^ Tilt the case assembly rearward at the top while lifting up until the core tubes clear the dash openings. 12. Core retaining straps (123). 13. Core (122). Install or Connect (Figures 5 through 10 and Figure 20) 1. Core (122) to the heater case (124).