Service Procedure
INSPECTION PROCEDURE
Determine if heater inlet hose is routed below heater outlet hose as shown in "INCORRECT" illustration.
If heater inlet hose is installed under heater outlet hose, "REROUTING PROCEDURE" below must be performed.
If heater inlet hose is routed as shown in "CORRECT" illustration, no further action is necessary. Install Campaign Identification Label and return vehicle to customer or to dealer stock.
REROUTING PROCEDURE
1. Park vehicle on a level surface.
2. Remove pressure cap from radiator when engine is cool by:
- Slowly rotating counterclockwise to detent. (Do not press down while rotating).
- Wait until any left-over pressure (indicated by a hissing sound) is released.
- After all hissing stops, press down on cap while continuing to rotate counterclockwise.
NOTICE:
TO AVOID BEING BURNED, DO NOT REMOVE RADIATOR CAP WHILE ENGINE IS AT NORMAL OPERATING TEMPERATURE. COOLING SYSTEM WILL RELEASE SCALDING FLUID AND STEAM UNDER PRESSURE IF CAP IS REMOVED WHILE ENGINE AND RADIATOR ARE STILL HOT.
3. With a clean drain pan in place, open radiator drain valve.
4. Once enough fluid has drained out of radiator:
- Remove screw from heater outlet hose bracket to cowl panel.
- Remove heater outlet hose from heater core tube (inboard tube) by squeezing both release tabs of quick connect fitting at base of heater core tube and pulling on pipe to disengage fitting (see quick connect fitting illustration).
5. Inspect inlet hose for signs of severe chafing and/or wear through (note that very few hoses are expected to be chafed or worn). If an inlet hose does require replacement, install new hose (P/N 10165021) following the procedures for the hose of the heater water control valve assembly on page 1B-26 of the 1992 Buick Roadmaster Service Manual.
6. Reposition outlet hose properly (under heater inlet hose), align orientation tabs with groves and push hose fitting in place then pull back on hose to ensure proper installation of connector.
NOTICE:
Make sure two "O" rings and nylon spacers are in position in quick connect fitting prior to reinstalling outlet hose connection.
Also, make certain quick connect fitting orientation tabs are aligned correctly before connecting quick connect fitting. If quick connect fitting is incorrectly connected, coolant leakage and damage to parts may occur. The quick connect fitting must be pushed on, then pulled back to verify proper connector engagement.
Do not rely on an audible click or visual verification to check for a proper connection. If it is necessary to repair quick connect connector, use approved service kit which can be obtained from GMSPO. (P/N 10164697)
7. Install outlet hose bracket and screw to cowl panel.
8. Check outboard inlet hose for clearance to A.I.R. pipe. Also, check to assure protective sleeve on heater outlet hose is under heater inlet hose.
9. Close radiator drain valve.
10. Pour drained coolant into radiator until tank is filled.
11. Start engine and run five (5) minutes (or until inlet hose is hot).
12. Top off radiator with coolant and install cap.
13. Fill coolant recovery reservoir to hot line with coolant.
NOTICE:
"Coolant" is 50/50 mix of water and ethylene glycol.
14. Install Campaign Identification Label.