SB-10057797-7487

INSTRUCTION TO SERVICE
ITS: 5930
SECTION:

231

WRITTEN BY:

Mike Pearson

SUBJECT:

Add EMP Radiator Ground Straps

Coolant System

ITS5930

THIS DOCUMENT AND THE CONTENTS DISCUSSED HEREIN ARE THE CONFIDENTIAL AND
PROPRIETARY INFORMATION OF NEW FLYER INDUSTRIES CANADA ULC AND NEW FLYER OF AMERICA
INC. AND ARE DISCLOSED BY NEW FLYER IN CONFIDENCE. THIS DOCUMENT AND THE CONTENTS
HEREIN ARE NOT TO BE DISCLOSED BY THE INTENDED RECIPIENT WITHOUT THE PRIOR WRITTEN
AUTHORIZATION OF NEW FLYER. ANY UNAUTHOIZED DISCLOSURE, REPRODUCTION OR OTHER
DISTRIBUTION OF THIS DOCUMENT OR INFORMATION IS STRICTLY PROHIBITED AND MAY RESULT IN
ACTION BEING TAKEN AGAINST THE PARTY MAKING THE UNAUTHORIZED DISCLOSURE. THIS
DOCUMENT AND ALL COPIES HEREOF MUST BE RETURNED TO NEW FLYER UPON REQUEST.

Bulletin Overview
If dissimilar metals have different electrode potentials, and come into contact with an electrolyte, one metal acts as
anode and the other as cathode. The electro potential difference between the dissimilar metals and the presence of
electrolytic (salt) solutions can be the driving force for an accelerated attack on the anode member of the galvanic
couple. The anode metal dissolves into the electrolyte, and deposits collect on the cathodic metal.
In normal service, voltage levels on coolant pipes have been found to be highly variable and can range anywhere
from roughly -1V to +1V.
These voltage levels are capable of causing highly-accelerated heat exchanger corrosion.
Voltage potential between radiator and coolant pipes can be eliminated by grounding the Mini-Hybrid® cooling system
and coolant pipes to the vehicle chassis.
Note:

If experiencing accelerated radiator corrosion, the work described in this bulletin must be completed
in order to maintain your 3 year EMP radiator warranty coverage. Failure to act promptly may affect
coverage for accelerated corrosion through the radiator due to stray current.

Figure 1: Mini-Hybrid® VPN 2020049001PA01 Cooling System

Issue
Radiator corrosion has been identified on buses with isolated pipe clamps on vehicles 2010 EPA or newer engines
and Mini-Hybrid® cooling systems including:

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Accelerated corrosion was located by the radiator outlet and was limited to vehicles running in icy
or snowy winter locations. This corrosion has been determined to be caused by stray voltage
carried by the coolant. If the pipes are separated from the radiator via silicone (non-conducting)
hoses and the pipes and radiator are not on the same ground plane, electrolysis can occur between
the pipes and the radiator. Grounding the radiator and pipes to the vehicle chassis eliminates the
electrical potential, stopping the electrolytic corrosion. See Figure 2 for images of accelerated
corrosion.

Figure 2: Gen II Examples.

PROCEDURE:
1. Turn the main battery disconnect switch to the “OFF” position.
2. Raise coach in accordance with the New Flyer Service Manual.
3. Typical coolant tube clamp ground strap mounting hardware orientation, see Figure 3.

Figure 3: Ground Strap Mounting Hardware Orientation

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4. Locate and remove the fir tree insert from the hole located on the rear of the existing radiator as shown in Figure
4. Disconnect any tyraps and or wires from the fir tree insert.
5. Drill out the existing hole from the fir tree insert using a 25/64” (0.390625) drill bit. Care is to be taken not to
damage the radiator behind the shroud when drilling.
Caution:

The use of a drill depth gauge is recommended to limit the depth of the hole to 0.50” or less to
avoid any damage to the radiator.

Drill out the existing
hole from the fir tree
insert using a 25/64”
drill bit
Figure 4: Fir Tree Mounting Hole
6. Install the rivnut from kit p/n 6449313 into the newly enlarged hole, see Figure 5.
7. To ground Mini-Hybrid® cooling system shroud secure the ¼” hook terminal end from the supplied 50” cable
using a flange head bolt supplied with kit p/n 6449008. If the removed tyrap was used to secure wires, also install
the p-clip from kit p/n 6449313 under the bolt head to secure the wires. Torque to 12±2 ft-lbs, see Figure 5.
8. Route ground wire to area approximately 4.5” forward of the welded rail (see Figure 10), routing wire away from
any hot surfaces or sharp edges. Use zip ties to secure wire at 18-24” intervals. Adjust cable orientation if
necessary.
Caution:

Grounding to the same welded assembly is required. Grounding to a bolted assembly is NOT
acceptable.
Insert Rivnut

Add p-clip
Drill using 25/64” drill bit

Insert the hook terminal
from the 50” cable
Flange Head Bolt 1/4”-20UNC x 0.75

50” cable assembly
Figure 5: Rivnut and Cable Installation

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Caution:

Fan shroud must not be grounded to the chassis unless the pipes are also grounded.

9. Install one of the 2.5” guillotine clamps from the parts kit to the existing upper radiator tube at the approximate
location and orientation shown in Figure 6, torque to 20 ±2 ft*lbs.
10. Attach the 3/8” ring tongue end of the 16” cable to the bottom stud of the guillotine clamp. Secure and orient the
hardware as shown in Figure 3. Torque the hardware to 20 ±2 ft*lbs.

11. Route ground wire to area approximately 4.5” forward of the welded rail (see Figure 10), routing wire
away from any hot surfaces or sharp edges. Adjust clamp locations on coolant pipes if necessary.
Upper radiator tube

2.5” Guillotine clamp

3/8” ring tongue end of
the 16” cable assembly
(see figure 2)

16” cable assembly

Figure 6: Radiator and Upper Coolant Tube Ground Strap Installation
12. Install one of the 2.5” guillotine clamps from the parts kit to the existing lower radiator tube at the approximate
location and orientation shown in Figure 7, 8 and 9. Lower radiator tube may vary in appearance. Torque to 20 ±2
ft*lbs.
13. Attach the 3/8” ring tongue end of the 50” cable to the stud of the clamp as per Figure 3. Secure using the
hardware supplied with the clamp. Torque the hardware to 20 ±2 ft*lbs. See Figure 7, 8 and 9.

14. Route ground wire to area approximately 4.5” forward of the welded rail (see Figure 10), routing wire
away from any hot surfaces or sharp edges. Use zip ties to secure wire at 18-24” intervals. Adjust
clamp locations on coolant pipes if necessary.

2.5” Guillotine clamp

Existing lower
radiator tube

3/8” ring tongue end of
the 50” cable assembly
(see figure 3)

50” cable assembly

Figure 7: Lower Radiator Tube Ground Strap

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Existing lower
radiator tube
3/8” ring tongue end of
the 50” cable assembly
(see figure 3)

50” cable assembly
2.5” Guillotine clamp

Figure 8: Lower Radiator Tube Ground Strap

3/8” ring tongue end of
the 50” cable assembly
(see figure 3)

50” cable assembly

Existing lower
radiator tube

2.5” Guillotine clamp

Figure 9: Lower Radiator Tube Ground Strap
15. Route ground wires to area approximately 4.5” forward of the welded rail (See Figure 10), routing wire away from
any hot surfaces or sharp edges. Use zip ties to secure wire at 18-24” intervals. Adjust clamp locations on coolant
pipes if necessary. Proceed with shroud ground wires before securing pipe grounds.
16. Drill a .281Ø (9/32”) hole thru outer wall of the streetside engine rail for grounding stud approximately 4.5” forward
of the bumper mount and 1” down from top of the engine rail. Remove structural coating from rail at washer
contact to allow for proper ground contact. Attach upper and lower radiator tube and shroud grounding straps.
Torque ¼ UNC x 1.00 bolt to 14 ft-lbs.
17. Apply a protective coating over the installation.
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Figure 10: Common Ground Point on Bus Frame

18. If necessary, lower coach in accordance with the New Flyer Service Manual.
19. Turn the main battery disconnect switch to the “ON” position.

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LABOUR ESTIMATE
Operation
1

Add EMP Radiator Ground Straps

Men

Hours

1

0.5

Labour Time
M X HR
0.5

PARTS REQUIRED
Item

Part Number

Description

1

6449008

Kit-EMP Radiator Ground Strap Rework

2

6449313

Kit-EMP Radiator Ground Strap Hardware

Qty.
per
Coach
1

Units

Notes

EA

Vpn 1370056042

1

EA

Vpn 1370049014

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