CAMPAIGN: ENGINE CYLINDER HEAD COOLANT PASSAGE BLOCKED
Model and Year: 1986 S/T-10 LIGHT DUTY TRUCK AND ASTRO VAN MODELS EQUIPPED WITH 2.5L L4 GAS ENGINE (RPO LN8)
General Motors has determined that some 1986 S/T-10 Light Duty Truck and Astro Van Models equipped with 2.5L L4 gas engine (RPO LN8) may have been produced with blocked cylinder head coolant passages. This condition can cause audible spark knock and/or engine overheating.
To determine if a vehicle may be affected by this condition it will be necessary to inspect the coolant passage for blockage. If blockage is found the cylinder head will be replaced.
INVOLVED VEHICLES
Involved are certain 1986 S/T-10 Light Duty Truck and Astro Van Models equipped with 2.5L L4 gas engine and built within the folloving vehicle identification number (VIN) breakpoints:
MODEL YEAR MODEL PLANT FROM THROUGH ---------- ----- ----- ----- ------- 1986 S/T-10 Moraine G2193946 G2208296 Shreveport G8180953 G8189777 1986 Astro Van Baltimore GB204352 GB217668
Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Iden- tification Number owner name and address data, and are furnished to the involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign.
These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle regis- tration data for any other purpose is a violation of law in several states. Accordingly you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.
OWNER NOTIFICATION
Owners vill be notified of this campaign an their vehicles by Chevrolet Motor Division (see copy of Owner Letter included with this bulletin).
DEALER CAMPAIGN RESPONSIBILITY
Dealers are to service all vehicles subject to this campaign at no charge to owners regardless of mileage, age of vehicle, or ownership, from this time forward.
Whenever a vehicle subject to this campaign is taken into your nev or used vehicle inventory or it is in your dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling or releasing the vehicle.
Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer and arrangements made to make the required modification according to instructions contained in this bulletin.
PARTS INFORMATION
Parts required to complete this modification are to be obtained from General Motors Warehousing and Distribution Division (GMWDD). To ensure these parts will be obtained as soon as possible they should be ordered from GMWDD on a C.I.O. order with no special instruction code but on an advise code (2).
QUANTITY PART NO. DESCRIPTION PER VEHICLE -------- ------------ ----------- 1052754 Coolant 1/2 Qt. 10007449 Thermostat Hsg. Gasket 1
When cylinder head replacement is required the folloving additional parts should be ordered. These parts should be ordered only when required.
QUANTITY PART NO. DESCRIPTION PER VEHICLE -------- ----------- ----------- 10037283 Cylinder Head 1 10035039 Cylinder Head Gasket 1 10026023 Intake Manifold Gasket 1 10004804 Exhaust Manifold Casket 1 3835333 Valve Stem Seals 8 1052915 RTV 1/4 Tube
SERVICE PROCEDURE
It is necessary to make a probe out of one of the following:
- Metal coat hanger - Straightened and approximately 12 inches long.
- Dipstick - Cut off twisted end.
Place a permanent mark 3.5 inches and 4.5 inches from one end of the probe. Then one inch from this same end put a 45 degree bend in the probe (see Illustration).
S/T TRUCK (WITH OR WITHOUT AIR CONDITIONING): -------------------------------------------- 1. Disconnect battery cable.
2. Drain engine of all coolant. Use a clean container and save the coolant for re-use.
3. Loosen generator adjustment bolts.
4. Remove generator belt.
5. Remove generator adjustment bolts.
6. Disconnect throttle cable at the intake manifold.
7. Remove generator adjustment pivot bracket and lay generator aside.
8. Disconnect coolant sensor wire.
9. Disconnect hose at thermostat housing.
10. Disconnect strut rod bracket at generator front bracket.
11. Remove generator front bracket.
12. Disconnect electrical harness at thermostat.
13. Disconnect electrical harness at air conditioning compressor.
14. Remove air conditioning compressor belt.
15. Remove air conditioning compressor bracket.
16. Disconnect air conditioning compressor harness.
17. Remove air conditioning compressor from bracketry and lay aside.
18. Remove air conditioning compressor front support bracket.
19. Disconnect upper radiator hose at thermostat housing.
20. Remove vacuum line bracket from thermostat housing.
21. Remove thermostat housing.
22. Insert the probe into the two cooling passages (see illustration). The probe is to be inserted a minimum of 4.5 inches into the manifold side coolant passage and 3.5 inches into the spark plug side coolant passage. If this can be done no further action is required. Proceed to step 23. If the probe will not slide into one or both passages even after several attempts the cylinder head must be replaced. Refer to SIT Truck Service Manual ST-369-86, Section 6A1 for removal and installation procedures then proceed to step 23.
23. Clean the thermostat housing and cylinder head of all old sealant.
24. Apply sealant GM P/N 1052915 or equivalent to the thermostat housing and install to the cylinder head.
25. Reverse steps 1-21 for parts re-installation. Refill cooling system using original coolant. Top off coolant with GM P/N 1052753 or equivalent mixed 50% with water.
26. Install Campaign Identification Label according to instructions contained in this bulletin.
SPECIFICATIONS:
-------------- Belt tension (old belts):
W/ A/C W/O A/C
Generator 400 N (90 lbs) 300 N (67 lbs) Air conditioning 400 N (90 lbs)
Thermostat Housing Bolts: 27 NM. (20 ft.lbs) 27 NM. (20 ft.lbs)
Generator Mounting torque:
Rear Bolt 27 NM. (20 ft.lbs) 27 NM. (20 ft.lbs) Lower Mounting Bolt 50 NM. (37 ft.lbs) 50 NM. (37 ft.lbs) Adjusting Arm Bolt 27 NM. (20 ft.lbs) 27 NM. (20 ft.lbs)
Compressor Mounting Bolts:
Front 43 NM. (32 ft.lbs) Rear 30 NM. (22 ft.lbs)
M-VAN (WITH OR WITHOUT AIR CONDITIONING):
1. Disconnect battery cable.
2. Drain engine of all coolant. Use a clean container and save the coolant for re-use.
3. Remove air intake and extension duct.
4. Remove oil fill tube.
5. Remove vacuum line bracket.
6. Remove upper radiator hose.
7. Remove generator belt.
8. Disconnect throttle cable at the intake manifold.
9. Remove generator adjustment pivot bracket.
10. Remove generator front bracket.
11. Disconnect hose at thermostat housing.
12. Disconnect electrical harness at thermostat.
13. Disconnect electrical harness at air conditioning compressor.
14. Remove air conditioning compressor belt.
15. Remove air conditioning compressor bracket.
16. Remove thermostat housing.
17. Insert the probe into the two cooling passages (see illustration). The probe is to be inserted a minimum of 4.5 inches into the manifold side coolant passage and 3.5 inches into the spark plug side coolant passage. If this can be done no further action is required. Proceed to step 18. If the probe will not slide into one or both passages even after several attempts the cylinder head must be replaced. Refer to the Astro Service Manual ST-372-86, Section 6Al for removal and installation instructions then proceed to step 18.
18. Clean the thermostat housing and cylinder head of all old sealant.
19. Apply sealant GM P/N 1052915 or equivalent to the thermostat housing and install to the cylinder head.
20. Reverse steps 1-16 for parts re-installation. Refill cooling system using original coolant. Top off coolant with GM P/N 1052753 or equivalent mixed 50% with water.
21. Install Campaign Identification Label according to instructions contained in this bulletin.
SPECIFICATIONS:
-------------- Belt tension (old belts): Generator 300 N (67 lbs) Air Conditioning 400 N (90 lbs)
Thermostat Housing Bolts: 27 NM. (20 ft.lbs)
Generator Mounting torque: Top Bracket Bolt 27 NM. (20 ft.lbs) Bottom Bracket Bolt 50 NM. (37 ft.lbs) Nut at back brace 42 NM. (30 ft.lbs)
Compressor Mounting Bolts: Front 43 NM. (32 ft.lbs) Rear 30 NM. (22 ft.lbs)
CAMPAIGN IDENTIFICATION LABEL
Each vehicle modified in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label." Each label provides a space to include the five digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or ballpaint pen.
Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.
Apply "Campaign Identification Label" only on a clean dry surface.
CLAIM INFORMATION
Submit a Product Campaign Claim with the information indicated below: * FAILED PARTS LABOR LAB OTH REPAIR PERFORMED PC PART NO. ALLOW FC OP HRS HRS ------------------------------------------------------------------------ INSPECT CYLINDER HEAD - 2 10007449 ** 00 V3670 0.8 0.1 1986 "S/T" TRUCK W/0 A/C INSPECT CYLINDER HEAD - 2 10007449 ** 00 V3671 1.2 0.1 1986 "S/T" TRUCK WITH A/C REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3672 6.3 0.1 1986 'S/T" TRUCK W/O A/C OR CRUISE REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3673 6.5 0.1 1986 "S/T" TRUCK WITH CRUISE ONLY REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3674 7.2 0.1 1986 "S/T" TRUCK WITH A/C ONLY REPIACE CYLINDER HEAD - 15 10037283 ** 00 V3675 7.4 0.1 1986 "S/T" TRUCK WITH A/C AND CRUISE INSPECT CYLINDER HEAD - 2 10007449 ** 00 V3676 1.0 0.1 1986 "M' VAN W/O A/C INSPECT CYLINDER HEAD - 2 10007449 ** 00 V3677 1.7 0.1 1986 "M" VAN WITH A/C REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3678 6.7 0.1 1986 "M" VAN W/0 A/C OR CRUISE REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3679 6.9 0.1 1986 "M" VAN WITH CRUISE ONLY REPIACE CYLINDER HEAD - 15 10037283 ** 00 V3680 8.0 0.1 1986 "M" VAN WITH A/C ONLY REPLACE CYLINDER HEAD - 15 10037283 ** 00 V3681 8.2 0.1 1986 "M" VAN WITH A/C AND CRUISE
*Campaign Administrative Allowance . **The "Parts Allowance" should be the sum total of the current GMWDD Dealer Net price plus 30% of all parts required for the repair.
Dealers will automatically recieve the correct labor and material allowance based on the labor operation performed.
Refer to the Chevrolet Claims Processing Manual for details on Product Campaign Claim submission.
(Notification Used By Chevrolet Motor Division)
Dear Chevrolet Owner:
General Motors has determined that some 1986 S/T-10 Light Duty Truck and Astro Van models equipped with 2.5L L4 gas engine may have been produced with blocked cylinder head coolant passages. This condition can cause audible spark knock and/or engine overheating.
To determine if your vehicle may be affected by this condition it will be necessary to inspect the coolant passage for blockage. If blockage is found the cylinder bead will be replaced.
Instructions have been sent to your Chevrolet Dealer. Parts are avail- able. Please contact your dealer to arrange a service date. The inspection and if necessary, cylinder head replacement will be performed at no charge to you. The inspection will take approximately two (2) hours and an additional six and a half (61/2) hours may also be needed if cylinder head replacement is required. Please ask your dealer if you wish to know how much additional time is needed to process your vehicle.
The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle please let us know by completing the postage paid owner reply card and returning it to us.
We are sorry to cause you this inconvenience; however we have taken this. action in the interest of your continued satisfaction with our products.
Chevrolet Motor Division GENERAL MOTORS CORPORATION
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.
