Functionality, Troubleshooting, Inspection, and Replacement for the 111-4374 Valve As (Check Valve Assembly) on Certain 3500 Commercial and Machine Engines {1355, 1393} Caterpillar

Generator Set

3512B (S/N: YAM1-UP)

3516B (S/N: YAT1-UP)

Hydraulic Shovel

6060 FS (S/N: DH31-UP)

Industrial Engine

3512C (S/N: MLM1-UP)

Marine Auxillary Engine

3512B (S/N: S2H1-UP)

3516B (S/N: S2R1-UP)

Marine Engine

3508B (S/N: S2E1-UP)

3508C (S/N: TTA1-UP; TTB1-UP)

3512B (S/N: S2J1-UP; S2L1-UP)

3512C (S/N: TTC1-UP; TTF1-UP; TTG1-UP)

3516B (S/N: S2X1-UP)

3516C (S/N: TTD1-UP; TTH1-UP)

Off Highway Truck

793D (S/N: FDB1-UP)

Power Module

PM3516 (S/N: NBR1-UP)

Truck

777D (S/N: AGC1-UP)

785C (S/N: APX1-UP)

789C (S/N: 2BW1-UP)

793C (S/N: ATY1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

The 111-4374 Valve As (Check Valve Assembly) is located within the water regulator housing. The check valve assembly has a composite body with an internal metal ball. The purpose of the check valve assembly is to purge air from the jacket water system during engine operation.

If the composite body of the check valve assembly is damaged, the check valve assembly fails to function properly, and cooler water from the radiator circuit is consistently bled off into the jacket water circuit. Symptoms of this failure mode range from longer than typical warmup times to consistent overcooling during low load operations.

We are aware of two examples where the composite body was damaged severely enough to all the metal ball to dislodge and circulate out through the water regulator housing, into the front bypass tube, through the jacket water pump, finally making contact with the oil cooler core. The symptoms of this failure mode would also include overcooling. If not identified and left unchecked, the metal could damage the oil cooler core enough to introduce cross contamination of the jacket water and engine lubrication system. This would best be identified through your S.O.S. monitoring.

Illustration 1	g06012627
Good 111-4374 Valve As (Check Valve Assembly)

Illustration 2	g06012629
Bad 111-4374 Valve As (Check Valve Assembly)

Illustration 3	g06012633
Engine oil cooler with minor damage.

Illustration 4	g06012637
Engine oil cooler with significant damage.

Solution

Add a metal cup plug to prevent the ball from falling out, damaging other cooling system components.

Illustration 5	g06012483
(A) 18.3 mm (0.720 inch) (1) Original check valve assembly bore (2) Drilled check valve assembly bore

1. Drill check valve assembly bore (1) in the regulator housing with a 17 ± 0.05 mm (0.670 ± 0.002 inch) drill bit to a depth of 18.3 mm (0.720 inch), to allow for the cup plug under the check valve.
   Show/hide table

   Illustration 6	g06012616
   (B) 7 mm (0.276 inch) Diameter (3) 0L-1022 Cup Plug

2. Drill a 7 mm (0.276 inch) hole through the center of cup plug (3). It is important that the diameter of the drilled passage (B) does not exceed the 8 mm (0.315 inch) diameter of the metal ball.
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   Illustration 7	g06012621
   (2) Drilled check valve assembly bore (3) 0L-1022 Cup Plug (4) 111-4374 Valve As (Check Valve Assembly)

3. Press drilled cup plug (3) into drilled check valve assembly bore (2) of the regulator housing.

4. Install new check valve assembly (4) into drilled check valve assembly bore (2) of the regulator housing.