G 2500 3/4 Ton Van V8-305 5.0L (1990)
Water Pump: Customer Interest
Heater - Insufficient Heat
File In Section: 1 - HVAC
Bulletin No.: 46-11-02
Date: November, 1994
Subject:
Insufficient Heater Performance (Install New Water Pump and Re-Route Heater Outlet Hose)
Models:
1990-94 Chevrolet and GMC Truck G Vans with 5.OL and 5.7L Engines (VINs H, K - RPOs L03, L05)
Condition
Some customers may comment on insufficient heat during cold weather operations. The heating system may be performing properly; however, the
customer may still be dissatisfied.
Cause
Inadequate warm up time from the heating system. In extreme cold environments, the heating system may be unsatisfactory if the vehicle is equipped
with only a front heating system. It may be necessary to install a second (rear) heating system.
Correction
Install a new water pump which will need a 1 inch long steel nipple, and re-route the heater outlet hose to the new water pump. This will improve the
warm up time for the heating system.
Service Procedure
Before installing the new water pump and re-routing the heater outlet hose, make sure that the heating system is functioning properly. There are a variety
of options which may effect the heating performance.
First, perform a function test. Before performing the function test, make sure that the engine coolant is hot and thermostat is open. This function test
procedure is located in the Service Manual Section 1A.
Check and verify that the following items are functioning properly. If not, repair as needed.
^
Low Coolant
^
Actuator mode door (temperature lever)
^
Thermostat
^
Waterflow obstructions
^
Airflow obstructions
^
Blower Motor Assembly
If the Heating system checks out to be functioning normally, install the new water pump (presently used on 4.3L engines) and reroute the heater outlet
hose from the radiator to the water pump assembly.
Removal Procedure
1.
Drain Coolant
2.
Remove water pump assembly.
