SERVICE BULLETIN
L-SERIES RADIATOR HOSE CLAMP-COOLANT
LEAK
GROUP: 0-GENERAL
SERVICE BULLETIN NO: SB-22-031
DATE: 12-21-2022
REF: HMM-221220-F1

SUBJECT VEHICLES: Certain 2022-2023 Model Year

L-Series Trucks Equipped with a Cummins B6.7 Engine.

Note: This technical service bulletin is provided as technical
information and is not authorization for a warrantable repair.
OVERVIEW:
The subject vehicles may exhibit coolant leaking from either the
inlet or outlet radiator hose connections of the radiator or auxiliary
transmission cooler. This leak may be due to reduced clamp
retention at these 4 locations. If a coolant leak is identified
coming from any of the 4 locations, this procedure provides
installation instructions and directions to install the new style hose
clamp at all 4 locations.
BEFORE YOU BEGIN:
• Read and understand all instructions before you begin the
work.
• Park the vehicle on a flat, level and solid surface.
• Place the gear shift lever in "Neutral" or "Park".
• Apply the parking brake firmly and confirm parking brake
activation.
• Turn off the engine and remove the key from the ignition
switch.
• Always wear safety glasses or goggles to protect your eyes.
• Place wheel chocks in front of and behind all the wheels to
prevent the vehicle from moving.
• Make certain that the engine and cooling system has
cooled down to an ambient temperature prior to
opening the cooling system or removing the degas
bottle cap.

PARTS:
Part Number

Part Description

Quantity

32960

Gates Power Grip
Hose Clamp
Fleetguard ES
Compleat OAT EG
50/50 - Red
Shell Rotella ELC
Nitrite Free 50/50 Red

4

N/A

N/A

As Needed

As Needed

VEHICLE PREPARATION:
1. Park the vehicle on a level and solid surface. Confirm the
engine is stopped, the starter switch is in the off (LOCK) position,
and the key is removed.

2. Apply the parking brake. Chock all of the wheels.

REPAIR PROCEDURE:
1. Is there coolant leaking from any one of the four radiator hose
locations?
YES – Proceed to STEP 2.
NO – This TSB (Technical Service Bulletin) does NOT apply to
this vehicle, disregard this bulletin and continue with your normal
diagnostics

2. Allow the engine and cooling system to cool down to ambient
temperature. Remove the engine coolant degas bottle cap from
the degas bottle. Open the radiator drain valve and drain the
coolant into a suitable clean container. Once the cooling system
is drained, close the radiator drain valve.
WARNING: Do not loosen or remove the degas bottle cap or
attempt to drain the cooling system until the coolant and engine
have cooled to ambient temperature. Loosening or removing the
degas bottle cap or draining the cooling system prior to the
cooling system cooling down could cause severe personal injury
due to scalding.

3. Loosen the 4 constant torque coolant hose clamps and
disconnect the following radiator hoses at each connection point:
- radiator inlet
- radiator outlet
- auxiliary transmission cooler inlet
- auxiliary transmission cooler outlet
Remove and discard the (4) constant torque clamps.

4. Using the new Gates PowerGrip hose clamps, remove the
cardboard brace by squeezing the clamp and cardboard brace as
illustrated in the picture below. Remove the cardboard brace and
discard.

5. Position 1 PowerGrip hose clamp over each of the 4 radiator
hoses. Reinstall the 4 radiator hoses to their corresponding
connection point.
- radiator inlet
- radiator outlet
- auxiliary transmission cooler inlet
- auxiliary transmission cooler outlet

6. Make certain that each of the 4 radiator hose connections are
fully seated onto the radiator and auxiliary transmission cooler
before proceeding. Position each of the Gates PowerGrip coolant
hose clamps 1/4inch (6mm) from the end of radiator hose, see
photographs below.

7. The Gates PowerGrip hose clamps will require heat to begin
shrinking and tightening them around the radiator hose. While
using a heat gun, apply heat to each of the 4 Gates PowerGrip
hose clamps. To prevent overheating the hose clamp or radiator
hose, continuously move the heat gun evenly heating as much of
the Gates Power Grip hose clamp as possible. The clamp should
begin to shrink and tighten after 30 to 60 seconds and may take 2
minutes for each clamp location.
NOTICE: Care should be taken to ensure that the Gates
PowerGrip hose clamp or radiator hose is not overheated and
damaged.
NOTICE: Once the engine reaches operating temperatures, the
Gates PowerGrip hose clamps will continue to shrink and tighten
at each of the 4 hose connections.

8. Slowly refill the cooling system and install the degas bottle cap
securely to the degas bottle. Start the engine and run the engine
until the engine and cooling system are at operating temperature.
NOTICE: During vehicle manufacturing, one of two different types
of engine coolant could have been used. To ensure the correct
replacement engine coolant is added to the cooling system,
inspect the degas bottle for an ATTENTION label. If an
ATTENTION label is affixed to the coolant degas bottle, then use
the Optional Cooling System Fluid Fill to top-off the cooling
system. If no label is found, then use the Standard Cooling
System Fluid Fill.
•
•

Standard Cooling System Fluid Fill
Fleetguard ES Compleat OAT EG 50/50
Optional Cooling System Fluid Fill
Shell Rotella ELC Nitrate Free 50/50

9. Recheck the 4 radiator hose connections where the Gates
PowerGrip hose clamps were installed. Make certain there are no
signs of engine coolant leaking before continuing to the next step.
10. This bulletin is complete, proceed to the FINAL INSPECTION
PROCEDURE.

FINAL INSPECTION PROCEDURE:
1. To complete this technical service bulletin, review the bulletin
and confirm the following:
•
•
•

Inspect the 4 radiator hose connections that received the Gate
PowerGrip hose clamps and make certain there are no
coolant leaks.
Make certain the correct coolant was used and that the
coolant level is full.
Engine coolant degas bottle cap is correctly installed.

CLAIM APPLICATION
Reimbursable in accordance within the terms and policies of the
Hino limited warranties.
Gates PowerGrip Radiator Hose Clamp Installation:
a)
b)
c)
d)
e)

Labor charge: 1.6 Hours
Warranty code: 13322
Trouble code: 12
Operation code: 13350AOT
Original failed part: 16581-EW100