Service Bulletin No. 3127
MODEL:

TYPE:

J4500, D-CRT

SECTION/GROUP:

Service Information

07-Electrical

DATE:
10/07/2019

SUBJECT:

Delco Alternator Cleaning Procedure
CONDITIONS:

Service Information Only
Description:
Motor Coach Industries (“MCI”) is instructing customers operating J4500 or D-CRT coaches equipped with a Delco 55
alternator MCI P/N: 07-03-1322, to clean the alternators and reapply corrosion inhibitor every 6000 miles, using the
following procedure as recommended by Delco.
This procedure is applicable to coaches starting MY19 and later.

Read this entire procedure before beginning work.
Use Safe Shop Practices At All Times.
To avoid personal injury:
a. Proper Personal Protective Equipment (PPE) must be worn. Safety glasses and
protective gloves are required for working with DEF Fluid.
b. Turn the main battery disconnect switch to the OFF position.
c. Ensure that both the front and the rear wheels are chocked.
d. Position the ENGINE RUN and ENGINE START switches on the engine
compartment remote control box to the OFF position.
e. Allow enough time for components to cool down prior to working in the engine
compartment
Motor Coach Industries Ltd.

Page 1 of 5

Service Bulletin No: 3127

1.0

Material requirements
No material required.

2.0

Special Tools
Coil Cleaning gun, MCI P/N: 20-00-0079.
Simple Green 1:1 solution.
CRC SP-400 corrosion inhibitor, MCI P/N: 23-02-0119, or the equivalent CRC Heavy duty corrosion
inhibitor, VPN: 06026.

3.0

Instructions
Water and common engine fluids are not harmful to the alternator or starter, but corrosives and
contaminants from road treatments can lead to premature failure if left to attack the alternator, cables, and
connections. Care should be taken to wash the chassis and engine components that may be impacted by
the contact. This procedure should be completed every 6000 miles, especially during periods of anti-icing
applications to the roadways.
This cleaning procedure needs to be completed with the engine running, allowing the hot water and
steam/water to be drawn into the alternator and flushing out the dirt, debris, as well as any corrosives and
contaminants from road treatment agents from the internal components of the alternator.

When working around a running engine, ensure no loose clothing and you are aware of all rotating
components.
When using a pressure washer or steam cleaner, wear a full-face shield and protective clothing.
1- Open the Engine door. T urn the Main Disconnect Switch and IGN “ON” and start the engine from the
rear engine control box and allow the engine to stabilize engine idle.

2- Wash down the alternators to remove any contaminants from the body, terminal studs, and internal
components. Using MCI P/N (20-00-0079) connected to a hot water source, use a mild detergent/cleaner
such as simple green 1:1 solution (1-part water and 1-part simple green) and wash down the alternators. Do
not use Zep formula 50 or Zep formula 940e as detergent. MCI P/N (20-00-0079) is an automatic metering
device which will ensure the correct concentration of detergent/cleaner allowed to enter the hot water
stream.
Motor Coach Industries Ltd.

Page 2 of 5

Service Bulletin No: 3127

CAUTIONS
Avoid the use of harsh/abrasive chemicals as these cleaners can be very difficult to rinse out and
can accelerate the corrosion attack on the components.
3- Steam clean both alternators to remove any residual detergent/cleaner from the exterior electrical studs
and internal mechanisms.

CAUTIONS
Avoid direct contact to the alternator from the high-pressure steam.
Ensure no ingress of chemicals, solvents or hot water/steam to the engine’s air induction system, as
internal engine damage may occur.
Protect other electrical components, openings, and wiring from the full force of the hot water and
steam.
4- Allow the engine to run for another 5 minutes to remove any remaining water within the alternators. Then
shut down the engine using the rear engine control box.
5- Access the alternators through the engine door.

Alternators on coaches equipped with DD13 engine

Motor Coach Industries Ltd.

Page 3 of 5

Service Bulletin No: 3127

Alternators on coaches equipped with ISX engine

Alternators on coaches equipped with X12 engine

6- Temporarily slide back the protective boots off the main power and ground cables.

Slide back the
protective cover

Allow the alternators to fully dry, then apply corrosion inhibitor CRC SP400 (MCI P/N:23-02-0119) or the
equivalent, CRC Heavy duty corrosion inhibitor VPN: 06026, liberally to the backside of the alternators,
ensuring the connections and grille are coated.

Corrosion inhibitor
CRC SP400

Motor Coach Industries Ltd.

CRC SP400. VPN:
03282, MCI P/N:
23-02-0119

Page 4 of 5

Service Bulletin No: 3127
Liberally spray the corrosion inhibitor on the openings on the side of the top alternator (highlighted in the
pictures below).

LH view of the alternator

Top view of the alternator

RH view of the alternator

After the corrosion inhibitor is dry, slide the protective boots back over the main power and ground cable
connections, taking care not to rub-off the corrosion inhibitor.
7- Then return the “Engine Start” and “Engine Run” switches back to their normal positions and close the
engine access and driver side service doors.

End of the procedure

Motor Coach Industries Ltd.

Page 5 of 5