C 1500 Truck 2WD V8-350 5.7L (1989)
Radiator: Customer Interest
Engine - Overheats When Towing
GMC NUMBER:
91-6B-45(A)
GROUP:
6B Engine Cooling
DATE:
March, 1991
CORPORATE
NUMBER:
066203R
SUBJECT:
ENGINE OVERHEAT WHEN TOWING OR DURING HEAVY USAGE
MODELS:
1988-91 C/K with 5.7L (VIN CODE K) ENGINE
THIS BULLETIN CANCELS AND REPLACES GMC TRUCK SERVICE BULLETIN 91-6B-45, DATED DECEMBER, 1991 TO CHANGE THE
LABOR OPERATION, LABOR TIME, AND TO UPDATE THE SERVICE PROCEDURE. ALL COPIES OF 91-6B-45 SHOULD BE DISCARDED.
Some 1988-91 C/K trucks equipped with 5.7L engines may experience an engine overheat condition (245 degrees F - 260 degrees F) while towing a
trailer or under heavy usage, yet during normal operation, without heavy load or trailer, the engine operates at a normal temperature (210 degrees F - 235
degrees F).
If this condition is encountered and cannot be repaired using procedures in the service manual, a larger capacity cooling system may be installed. This
larger capacity cooling system typically reduces engine operating temperatures by 20-25 degrees while towing a trailer or under heavy usage.
Important
This larger capacity cooling system is not intended for correcting engine overheats that occur while idling or under normal operating conditions.
NOTE: It will be necessary to install new engine oil cooler hoses on models equipped with an internal (inside radiator) engine oil cooler on models wlth
an externally (outside radiator) mounted engine oil cooler, the installation will require the removal of the external oil cooler and hoses. They will be
replaced by the internal (inside radiator) engine oil cooler, which this larger capacity radiator features, and the required oil cooler hoses.
SERVICE PARTS INFORMATION:
Part
Quantity
Number
Description
1
52457632
Radiator (auto. & manual
trans.)
1
15650248
Shroud (upper)
1
15650247
Shroud (lower)
2
15553981
Insulator (upper)
2
15591853
Insulator (lower)
1
15574276
Bracket (right)
1
15574275
Bracket (left)
1
15627103
Radiator Hose (upper)
1
15629092
Radiator Hose (lower)
1
12076298
Protector (lower radiator
hose)
1
15574167
Baffle
1
15552389
Deflector
3
11513687
Bolt (rad. support baffle)
2
11509363
Bolt (rad. mounting bracket)
1
15611492
Hose (outlet) "C" models
1
15623000
Hose (inlet) "C" models
1
15611493
Hose (outlet) "K" models
1
15622999
Hose (inlet) "K" models
Parts are currently available from GMSPO.
INSTALLATION PROCEDURE:
