Instructions on How to Replace a Heater Core in a 1991 Park Avenue

The heater core is one of the central elements of an automobile's heating system. A bad heater core will often leak coolant into the passenger compartment -- a sure sign that you must replace it. You need to work on both the engine and passenger side of your Buick Park Avenue to remove and replace the heater core. This will involve removing parts of the dashboard.

Instructions

Removal

1

Disconnect the car's battery, removing the negative cable first and then the positive one.

2

Raise the car's front end with a jack and support it on jack stands. Make sure the parking brake is applied.

3

Drain the engine coolant into a large container using the petcock at the lower left corner of the radiator. Once all the coolant is drained there, drain the remnants at the engine block drain plugs.

4

Disconnect the drain hose at the bottom end of the heater case and the heater hoses from the engine compartment firewall, loosening the hose clamps with a flat screwdriver.

5

Unscrew and remove the right sound insulator from the bottom of the dash and the steering column's trim cover. Pry out the heater's outlet duct--it may take a trim stick--and then open, unscrew and remove the glove box.

6

Remove the heater core cover, pulling it straight back so you don't break the drain tube.

7

Remove the clamps for the heater core and remove the core from the housing.

Installation

8

Insert the replacement heater hose into the housing with its clamps, then reconnect the heater core cover.

9

Reconnect the glove box, heater duct, steering column cover and dashboard sound insulator.

10

Connect the drain hose and heater hoses back to the core and heater case using their hose clamps.

11

Lower the car off the jack stands.

12

Fill the radiator with the engine coolant; use fresh water and coolant if the old coolant is contaminated.

13

Reconnect the car battery starting with the positive cable.