QUICK SERV. INFO.-DIESEL ITEMS MULTIPLE SUBJECTS

THIS BULLETIN CONTAINS MULTIPLE SUBJECTS. PAGE THROUGH TO DESIRED SUBJECT.

GR. 6D ELC WIRING ON SOME DIESEL C-CARS

ON SOME DIESEL C-CARS, THE ELECTRONIC LEVEL CONTROL WIRING IN THE RELAY CENTER MAY BE INCORRECT, CAUSING THE COMPRESSOR TO RUN CON- TINOUSLY. THE ELC RELAY CONNECTION IN THE RELAY CENTER HAS 5 CAVITIE AND 4 WIRES; THE CENTER CAVITY SHOULD BE BLANK. THE INCORRECT AND CORRECT WIRING SCHEMES ARE SHOWN BELOW. (SEE BULLETIN 81-11)

GR. 6A DIESEL INJECTION PUMP COVER INSTALLATION STEP CORRECTION

DSTB 80-T-7 ON CORRECTING DIESEL INJECTION PUMP LEAKS HAS AN IN- CORRECT STEP 10, PAGE 6, ON INSTALLING THE PUMP COVER SEAL AND COVER. THE CORRECTED STEP SHOULD READ THE SAME AS STEP 21 ON PAGE 4 OF THE BULLETIN.

GR. 6A DIESEL IDLE

ON SOME 1980 DIESEL CARS, THE "FUEL INJECTION PUMP SHAFT SPRING" SHOW IN FIGURE 6A-180 OF THE 1980 CADILLAC SERVICE MANUAL MAY BE MISSING. THE ABSENCE OF THIS SPRING COULD AFFECT THE IDLE CHARACTERISTICS OF THE ENGINE. THE SPRING IS AVAILABLE FROM GMPD AS PART NO. 22502241.

GR. 6A VALVE LIFTER BLEED DOWN PROCEDURE - 1978-1981 DIESEL

A NEW VALVE LIFTER BLEED DOWN PROCEDURE HAS BEEN DEVELOPED FOR ALL 1978 THROUGH 1981 DIESEL ENGINES. IF THE ROCKER ARMS HAVE BEEN LOOSENED OR REMOVED THE VALVE LIFTER CAN BE BLED DOWN BY THE FOLLOWING PROCEDURE:

1. BEFORE INSTALLING ANY REMOVED ROCKER ARMS, ROTATE THE ENGINE CRANKSHAFT TO A POSITION OF NO. 1 CYLINDER BEING 32 DEG. BEFORE TOP DEAD CENTER. THIS IS 14MM (1/2") BEYOND THE END OF THE TIMING INDICATOR. IT MAY BE NECESSARY TO REMOVE NO. 1 CYLINDER GLOW PLUG TO DETERMINE IF THE POSITION OF THE PISTON IS CORRECT. THE COMPRESSION PRESSURE WILL TELL YOU THAT YOU ARE IN THE RIGHT POSITION.

NOTICE: USE ONLY HAND TOOLS TO TORQUE THE ROCKER ARM PIVOT BOLTS TO AVOID ENGINE DAMAGE.

2. IF REMOVED, INSTALL THE NO. 5 CYLINDER PIVOT AND ROCKER ARMS. TORQUE THE BOLTS ALTERNATELY BETWEEN THE INTAKE AND EXHAUST VALVES UNTIL THE EXHAUST VALVE BEGINS TO OPEN, THEN STOP.

3. INSTALL REMAINING ARMS.

4. WHEN INSTALLING NO. 3 AND NO. 8 INTAKE VALVES (IF THESE ROCKER ARMS WERE REMOVED) DO NOT TORQUE THE INTAKE VALVE PIVOTS BEYOND THE POINT THAT THE VALVE WOULD BE FULLY OPEN. THIS IS IN- DICATED BY STRONG RESISTANCE WHILE STILL TURNING THE PIVOT RE- TAINING BOLTS. GOING BEYOND THIS WILL BEND THE PUSH ROD. TORQUE THE BOLTS SLOWLY ALLOWING THE LIFTER TO BLEED DOWN.

5. FINISH TORQUING NO. 5 CYLINDER ROCKER ARM PIVOT BOLTS 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 RETAING BOLTS. GOING BEYOND THIS WILL BEND THE PUSH ROD.

6. DO NOT TURN THE ENGINE CRANKSHAFT FOR AT LEAST 45 MINUTES.

7. FINISH REASSEMBLING THE ENGINE AS THE LIFTERS ARE BEING BLED.

NOTICE: DO NOT ROTATE THE ENGINE UNTIL THE VALVE LIFTER HAVE BEEN BLED DOWN, OR DAMAGE TO THE VALVE TRAIN COULD OCCUR.

GR. 6C WATER-IN-FUEL NOTICE

WE HAVE RECEIVED SOME COMMENTS OF THE WATER-IN-FUEL NOTICE (PROVIDED IN THE KIT) NOT BEING PLACED IN THE GLOVE BOX WHEN A WATER-INFUEL SENSOR KIT IS INSTALLED IN A CAR.

IT IS IMPORTANT THAT THIS NOTICE, EXPLAINING THE OPERATION OF THE SYSTEM, BE REVIEWED WITH THE CUSTOMER AND RETAINED IN THE GLOVE BOX FOR FUTURE OWNER REFERENCE.

GR. 6D DIESEL FAST GLOW RELAY PRECAUTION

THE DIESEL ENGINE FAST GLOW CONTROL SYSTEM FROM 1979 THROUGH 1981 CADILLAC CARS REQUIRES THE USE OF A HEAVY DUTY CONTROL RELAY,PART NUMBER 560580. THIS RELAY IS MOUNTED ON THE RIGHT SIDE INNER FENDER PANEL, AND CONTROLS THE FLOW OF CURRENT FROM THE BATTERY TO THE GLOW PLUGS.

THE GLOW PLUG RELAY MUST NOT BE BYPASSED FOR ANY REASON. JUMPING THE RELAY TO ENERGIZE THE GLOW PLUGS BYPASSES THE INTERNAL CICUITRY THAT CONTROLS THE TEMPERATURE RELATIONSHIP AT THE PLUGS. THIS ACTION WILL CAUSE THE GLOW PLUGS TO BURN OUT.

GR. 6A 1981 DIESEL CYLINDER HEAD GASKET

DUE TO DOWEL PIN LOCATION ON 1981 DIESEL ENGINES, IT IS POSSIBLE TO INSTALL THE CYLINDER HEAD GASKET UPSIDE DOWN. ON ALL 1981 DIESEL ENGINES, THE PRECHAMBER SHIELD ON THE HEAD GASKET MUST BE INSTALLED TOWARD THE CYLINDER HEAD. A DOWEL PIN WILL BE ADDED TO THE CYLINDER BLOCK TO PREVENT INCORRECT INSTALLATION OF CYLINDER HEAD GASKETS.

GR. 6C PURGING AIR FROM DIESEL INJECTION PUMP

TO REDUCE THE TIME REQUIRED TO PURGE AIR FROM THE INJECTION PUMP, WHEN CHANGING THE FUEL FILTER OR WHEN THE CAR HAS RUN OUT OF FUEL, DISCONNECT THE CONNECTOR FROM THE TEMPERATURE SWITCH AND JUMPER CONNECTOR TERMINALS. THIS WILL AID IN PURGING AIR FROM THE PUMP. (THIS PROCEDURE IS NECESSARY ONLY ON A HOT ENGINE, AS THE CIRUIT WILL ALWAYS BE CLOSED WHEN THE ENGINE IS COLD.)

GR. 6C USE OF STARTER FLUIDS IN DIESEL ENGINES

THIS IS TO ADVISE THAT STARTER FLUIDS SUCH AS ETHER OR OTHER UCH STARTING AIDS MUST NOT BE USED IN DIESEL ENGINES INSTALLED INCADILLAC CARS. USE OF THESE FLUIDS CAN CAUSE SEVERE INTERNAL ENGINE DMAGE.

WE ASK THAT THE ABOVE INFORMATION BE BROUGHT TO THE ATTENTIONOF OWNERS AND THOSE IN YOUR DEALERSHIP RESPONSIBLE FOR WORKING OOR MOVING DIESEL EQUIPPED VEHICLES.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.