GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Diesel Engine Valve Lifter Bleed-Down

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If the rocker arms have been loosened or removed, but the intake manifold was not removed, only the bleed-down procedure need be performed.

REMOVAL




WARNING
Keep lifters and pushrods in order! This is absolutely necessary for installation, since these parts have differences which could result in engine damage if not installed in their original positions!

  1. Remove intake manifold.
  2.  
  3. Remove valve covers, rocker arm assemblies and pushrods.
  4.  
  5. Remove the valve lifter guide retainer bolts.
  6.  
  7. Remove the retainer guides and valve lifters.
  8.  

DISASSEMBLY



  1. Remove the lifters.
  2.  
  3. Remove the retainer ring with a small screwdriver.
  4.  
  5. Remove pushrod seat and oil metering valve.
  6.  
  7. Remove plunger and plunger spring.
  8.  
  9. Remove check valve retainer from plunger, then remove valve and spring.
  10.  

CLEANING & INSPECTION



After lifters are disassembled, all parts should be cleaned in clean solvent. A small particle of foreign material under the check valve will cause malfunctioning of the lifter. Close inspection should be made for nicks, burrs or scoring of parts. If either the roller body or plunger is defective, replace with a new lifter assembly. Whenever lifters are removed, check as follows:

  1. Roller should rotate freely, but without excessive play.
  2.  
  3. Check for missing or broken needle bearings.
  4.  
  5. Roller should be free of pits or roughness. If present, check camshaft for similar condition. If pits or roughness are evident replace lifter and camshaft.
  6.  

ASSEMBLY



  1. Coat all lifter parts with a coating of clean kerosene or diesel fuel.
  2.  
  3. Assemble the ball check, spring and retainer into the plunger.
  4.  
  5. Install plunger spring over check retainer.
  6.  
  7. Hold plunger with spring up and insert into lifter body. Hold plunger vertically to prevent cocking spring.
  8.  
  9. Submerge the lifter in clean kerosene or diesel fuel.
  10.  
  11. Install oil metering valve and pushrod seat into lifter and install retaining ring.
  12.  
  13. Prime new lifters by working the lifter plunger while submerged in kerosene or diesel fuel.
  14.  
  15. Install the lifters.
  16.  
  17. Perform the bleed-down procedure.
  18.  

BLEED-DOWN



  1. Before installing any removed rocker arms, rotate the engine crankshaft so the No. 1 cylinder is 32° before top dead center. This is a 2 in. (50mm) counterclockwise from the 0 pointer. If only the right valve cover was removed, remove No. 1 cylinder's glow plug to determine if the position of the piston is the correct one. The compression pressure will tell you that you are in the right position. If the left valve cover was removed, rotate the crankshaft until the No. 5 cylinder intake valve pushrod ball is 0.28 in. (7.0mm) above the No. 5 cylinder exhaust valve pushrod ball.
  2.  

Use only hand wrenches to tighten the rocker arm pivot nuts to avoid engine damage.

  1. If removed, install the No. 5 cylinder pivot and rocker arms. Tighten the nuts alternately between the intake and exhaust valves until the intake valve begins to open, then stop.
  2.  
  3. Install remaining rocker arms except No. 3 exhaust valve. (If this rocker arm was removed).
  4.  
  5. If removed, install, but do not tighten the No. 3 valve pivots beyond the point that the valve would be fully open. This is indicated by strong resistance while still turning the pivot retaining bolts. Going beyond this would bend the pushrod. Tighten the nuts SLOWLY allowing the lifter to bleed down.
  6.  
  7. Finish tightening the No. 5 cylinder rocker arm pivot nut SLOWLY. Do not go beyond the point that the valve would be fully open. This is indicated by strong resistance while still turning the pivot retaining bolts. Going beyond this would bend the pushrod.
  8.  
  9. DO NOT turn the engine crankshaft for at least 45 minutes.
  10.  
  11. Finish reassembling the engine as the lifters are being bled.
  12.  

Do not rotate the engine until the valve lifters have been bled down, or damage to the engine will occur.

 
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