1993/01/25 Caterpillar

Unit Injector Tip Seal Deterioration {1290}

Usage:

1.1 Liter Family Of Engines

In some cases the deterioration of the 328970 O-Ring Seal at the bottom of the unit injector has been reported as the cause of combustion leakage around the injector. The purpose of this seal is to provide initial sealing until the unit injector seats in the 7W5749 Sleeve (brass) in the cylinder head. The injector seats in the sleeve almost immediately after the initial engine start up. Therefore, deterioration of the 328970 O-Ring Seal will not result in combustion leakage. It is normal for this seal to deteriorate over time due to exposure to the hot combustion gasses.

Whenever the unit injector is removed, both the tip and body seals should be replaced. The seating surface of the brass sleeve should be inspected and replaced if necessary.

Location of the 328970 O-Ring Seal (tip).

Caterpillar Information System:

1993/01/25 Drive End Bearing Service For 50/75 Amp Brushless Alternators {1405}

1993/01/25 Special Instruction For Installing VR3 Voltage Regulator On SR4 Generators Now Available {4450}

1993/01/25 New Connecting Rod Bearing Used In Piston And Rod Groups {1219}

1993/01/18 New Cylinder Head Group Used To Help Reduce The Amount Of Oil On The Valve Stems {1102,1109,1104}

1993/01/18 New Exhaust Manifold Group Will Help Reduce Vibration On Bellows {1059}

1993/01/18 New Grommets With Higher Temperature Capacity Used In Clamp Assemblies {1307,1052}

1993/01/18 New And Remanufactured Fuel Injector Reference {1290}

1993/01/18 Cylinder Pack Puller Groups Improved {0705,1239}

1993/01/18 Part Number References For 0R2818, 0R2819, And 0R3231 Remanufactured 3208 Truck Engines {0374}

1993/01/18 New Videotape "Detection of Air and Combustion Gases in the Cooling System" Available {0374,1350}

1992/12/21 New Bellows Assemblies Used In Turbocharger Groups{1052,1059}

1992/12/21 Modifying Former 2W8888 Rocker Arm Shaft For Use With New 8T7581 Rocker Arm Shaft Bolt{1102}

1993/01/25 Check Engine Water Pump Impeller Face Clearance If The Engine Experiences Symptoms Of Overheating {1361}

1993/02/01 New 9U6101 Lower Pilot Reamer Group Available{0670,1125}

1993/02/08 Maintenance Tips For 6I0799 Exhaust Restrictor; Additional Spring Improves Performance Of 6I0799 Exhaust Restrictor{1119,1061,1088}

1993/02/15 Procedure To Determine Idler Height {4159}

1993/02/15 Aftercooler Core And Turbocharger Compressor Wheel Cleaning Interval {1317,1052,1054,1060}

1993/02/15 New Breather Group And Fumes Disposal Group Help Reduce Oil In Blow-By Fumes {1317}

1993/02/15 New Tank Assemblies Used In Expansion Tank Groups; New Pressure Cap; New Coolant Recovery System Available {1354,1392}

1993/02/15 Maximum Wiring Harness Extension Length Specification {1408,7451}

1993/02/15 New Oil Pump Groups Do Not Require Key On Drive Shaft {1304}

1993/02/15 Valve Seat Insert Removal Tools {0703,1103}

1993/02/15 New Water Seals Used In Cylinder Head Groups; New Water Seal Assemblies And O-Ring Seals Used In Insert Kit {1115}

1993/02/15 Low Idle Operating Expense