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.


# ITEMS 13 THROUGH 15 APPLY TO TRUCKS EQUIPPED WITH AIR CONDITIONING.


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SERVICE PROCEDURE (CONT'D)

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 3.5 inches into the right (passenger side) coolant passage and 4.5 inches into the left (driver 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 6A1 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)


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