Update For Diesel Engines With Trap Oxidizer
TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERSDATE: January, 1985 (supersedes MBNA 20/4) REF. NO. MBNA 20/4a
SUBJECT: ENGINE BLOCK HEATER INSTALLATION MODELS 107, 123, 126, 201 AND 1985 MODELS 123 AND 126.120 WITH TRAP OXIDIZER
Diesel Engines with Trap Oxidizer
The attached Work instructions No. 170 detail the block heater installation into diesel engines with trap oxidizer and should be filed with Work Instructions No. 152, 153, 154, 155 and 156. The block heater described in the Work Instructions is of the earlier type and part of a kit that is available under the new part no. 900 203 49 95. Only this kit must be used for engines equipped with trap oxidizer.
All Gasoline Engines and Diesel Engines as of Model Year 1980
Work Instructions No. 152-156 detailing the installation of the new block heater kit (part no. 901 203 00 95) remain valid for engines 616.912 and 617.912 starting with Model Year 1980, as well as engine types 102.961, 102.985, 116.96/117.96, 601.21 and 617.95 without trap oxidizer.
However, in Work Instructions No. 155, the following addition should be made where appropriate:
As of model year 1985, the core plug in engine 102 is identical to engine 601. Remove the core plug with a 22 mm six-point socket and install the block heater with an O-ring, similar to engine 601.
In general, install the block heater with the same type seal used with the core plug. Always install an aluminum seal if the core plug had no seal ring.
Naturally Aspirated Diesel Engines Prior to Model Year 1980
The previous block heater kit remains applicable for all naturally aspirated diesel engines prior to Model Year 1980. This kit is now part no. 900 203 49 95.
WORK INSTRUCTIONS
No. 170 Date
January, 1985
File Ref.
Group
20
1. Disconnect battery ground cable.
2. Drain coolant from radiator into clean container for reuse.
3. Disconnect steering shock absorber.
4. Remove starter motor mounting bolts and turn steering linkage as required to remove starter motor.
Figure 1 - Drain Plug and Core Plug:
5. Drain coolant from engine block by removing drain plug (1, Figure 1).
6. Remove core plug from engine block using a 19 mm (3/4 in.) Allenhead driver (2, Figure 1).
7. Reinstall engine block drain plug with a new seal ring. Close radiator drain.
8. Pre-assemble heating element into adapter bushing using MB sealer, part number 001 989 25 20. Loctite pipe sealer 59214, or tape and torque to 70 N-m (52 ft.lbs).
9. Install pre-assembled block heater into engine block with an aluminum seal ring supplied in kit, apply sealer (see step 8) and tighten firmly.
10. Reinstall starter motor and steering shock absorber.
Figure 2 - Tie Cable to Supports:
11. Attach power cable to block heater (arrow), guide it through the insulated clamp at the lower starter motor bracket and route it along suitable supports on the right side so that it ends in front of the radiator. Tie cable with plastic straps to the supports as required (Figure 2).
12. After checking coolant for sufficient antifreeze protection, refill cooling system and pressure test for leaks.
13. Reconnect battery ground cable.
14. Run engine to operating temperature with defroster on. Check for proper coolant level, heater operation and leaks.
Parts Information
Part Name Part Number
Block heater kit 900 203 49 95
Time Allowance
20-0955 35 Block heater, Subsequent installation 2.5 hours
36 (California vehicles, M.Y. 1985
37 and later vehicles with trap oxider)
56