GUIDE ASSEM. 9L4181 - Caterpillar

CONFIDENTIAL TIBU4349-01
TECHNICAL INFORMATION BULLETIN NOVEMBER 03, 2004
MACHINE ENGINE 3126B 5GG(5180-5900)
INDUSTRIAL ENGINE 3126B BEJ(5750-6750)
ON-HIGHWAY TRUCK ENGINE 3126E LEF(142-199)
C7 KAL(26000-51000)
C7 FML(21)
C7 FMM(34-36)
3126B 6PZ(3274-3769)
3126B 7JZ(6737-7050)
Component Code(s) 1100SUBJECT: OIL IN COOLANT DIAGNOSTIC FOR 3126B, 3126E, AND C7 ENGINES
PROBLEM:
Some cylinder heads for 3126B Machine Engines, 3126B Industrial Engines, 3126B, 3126E, or C7 On-highway Truck Engines may be leaking oil into the coolant due to cracks in the injector bore(s).
This problem has been found to only occur on a small percentage of the heads that have a casting mark that is found in the location that is shown in Figure 1. The engines will have a serial number that is in one of the ranges that are identified at the beginning of this document.
The actual casting numbers may be different on your engine.
SOLUTION:
For all oil in coolant complaints on engines in the suspect serial number ranges, you must perform the following diagnostic to determine if the cylinder head is the source of the oil leak. This procedure should be followed prior to any other diagnostic procedure unless the cause for the oil in coolant symptom is obvious:
1. Install a pressure gauge on the cooling system.
2. Run engine until the normal operating temperature is reached and stabilizes.
3. Note the pressure reading on the cooling system.
4. Using Caterpillar® Electronic Technician (ET), initiate the Injection Actuation Test. Use Cat® ET to step up the actuation pressure to the highest step.
5. Monitor the pressure on the cooling system (you may need to allow the engine to run for 15 to 20 minutes.)
If the pressure reading on the cooling system pressure gauge increases 55 kPa (8 psi) or more beyond the pressure that was recorded in Step 3, record the amount of increase and contact your TC for assistance.
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