K 1500 Suburban 4WD V8-393 6.5L DSL Turbo (1994)
Engine Oil Pressure: Customer Interest
Engine - Loss of Oil Pressure or Turbocharger Failure
File in Section: 6 - Engine
Bulletin No.: 47-61-27
Date: September, 1994
Subject:
Loss of Engine Oil Pressure or Turbocharger Failure (Inspect/Replace Oil Gallery Plugs)
Models:
1994 Chevrolet and GMC Truck C/K, G and P Models with 6.5L Diesel Engine (VINs F, P, S, Y - RPOs L65, L49, L56, L57)
Note:
This bulletin addresses engine service prohibited in the engine exchange bulletin 376115A. If, however, there is no major engine damage and the oil
gallery cup plugs have failed, these instructions take priority over those found in bulletin 376115A.
Condition:
Some owners may experience a loss of or lower oil pressure if the left oil gallery cup plug falls out, or turbocharger failure in addition to loss of oil
pressure if the right oil gallery cup plug falls out.
Cause:
A small number of production engines built prior to April 1, 1994, may have had too much chamfer on oil gallery plug bores. As a result, the cup plug
did not fit properly in the chamfered area and could pop out.
Correction:
If the vehicle has lower oil pressure (specs: 10 psi at idle - hot; 40 to 45 psi at 2000 RPM) and it can be verified using a manual gauge, remove the front
cover and inspect the oil gallery cup plugs. If the left plug has fallen out, inspect the engine's main and rod bearings. The front rod bearing (# 1) and front
main bearing (# 1) will be the first to fail. If inspection indicates the bearings are not damaged, replace both oil gallery plugs. If inspection finds damage
to the bearings, replace the engine. See parts and installation information for proper procedures.
If the turbocharger failed because of loss of oil feed, remove the front cover and inspect the right oil gallery cup plug. If the right cup plug has fallen out,
replace both oil gallery cup plugs. When the turbocharger has failed, inspect the intake system to the engine and oil return tube for any metal shavings. If
metal shavings have entered the engine, replace the engine. See parts and installation information for proper repair procedures.
Instruction:
After inspecting the engine, verifying there is no further damage and the cup plugs only need to be replaced, perform the following:
Remove the engine front cover and timing gears to replace the cup plugs. Follow instructions in the service manual for proper procedures.
Notice:
If the timing chain, timing gears, front cover, crankshaft or other component(s) affecting timing are replaced, it will be necessary to reprogram TDC
Offset into the PCM. Refer to bulletin 476508 (VINs F, P, S - RPOs L65, L49, L56 only). For VIN Y - RPO L57, follow service manual procedure.
1.
Remove both plugs from oil gallery; see Figure 1 for location of plugs.
