Replacing coolant lines of AdBlue® heating
It has been determined that, in many cases, the coolant lines of the AdBlue® heating were not replaced when processing vehicles in deficiency phase 3/4. This also applies to variants on which the coolant lines of the AdBlue® heating are made of plastic. We would like to inform you that soiling/deposits in the coolant lines cannot be worked loose by flushing. Failure to replace the coolant hoses and the plastic coolant lines can lead to renewed sludging in the engine cooling system.
Reusing coolant added directly after the flushing process
Furthermore, we would like to point out once again that coolant which was added immediately after flushing must be disposed of. The first passivation of the engine cooling system diminishes the chemistry of the coolant considerably. If this coolant is added again, it can result in renewed sludging.
Repeated sludging
If it is determined after repeated sludging that the procedure does not match current flush documentation, the extra costs that occur as a result will be reverse-charged to the service operation in future.
Operations
A number of operation items have been changed on the system side. These changes will be apparent as of the middle of April 2019. The new and modified operation items as given in AH20.00-N-0002-02H (Notes on further work in case of coolant sludging) can be found in the attached tables. The respective additional operations are not listed and must be applied separately.
Overview of operation items connected to sludging of the coolant: |
Scope | Operation text | Operation position no. | Phase 1 | Phase 2 | Phase 3/4 |
Tests | Determine deficiency phase of coolant in event of sludging (stand-alone operation) | 20-1200 | X | X | X |
Check flow volume of heater core (coolant drained) | 83-1009 | - | X | (x) | |
Coolant | Completely drain off and replace coolant (after check) on veh. with code B3H | 20-1158 | X | X | X |
Flushing | Flush engine cooling system with flushing unit (deficiency phase determined) | 20-1201 | - | X | X |
Flush engine radiator and heater core (engine cooling system flushed) on veh. in deficiency phase 2 | 20-1203 | - | X | - | |
Coolant filter | Replace coolant filter element (engine cooling system flushed) | 20-1052 | (x) | x (A) | x (A) |
Retrofit coolant filter (drain coolant) | 20-1272 | - | x (B) | x (B) | |
Coolant expansion reservoir | Convert front coolant expansion reservoir with coolant pressure control solenoid valve (engine cooling system flushed) | 20-5420 | - | x (A) | x (A) |
Replace coolant expansion reservoir (coolant drained) | 20-5415 | - | x (B) | x (B) | |
Engine radiator | Replace engine radiator (engine cooling system flushed) | 20-3919 | - | - | X |
Heater core for heater | Remove/install heat exchanger for heater, replace if necessary (coolant drained) on veh. with air conditioning | 83-3421 | - | - | x (A) |
Remove/install heat exchanger for heater, replace if necessary (coolant drained) on veh. with automatic air conditioning (HVAC) | 83-3422 | - | - | x (B) | |
Remove/install heat exchanger for heater, replace if necessary (coolant drained) | 83-3401 | - | - | x (C) | |
Coolant hoses | Replace main coolant hoses A to J (engine cooling system flushed) | 20-7484 | - | - | X |
Replace all other coolant hoses (engine cooling system flushed) | 20-7480 | - | - | X | |
Circulation pump for residual heat utilization | Replace circulation pump for residual heat utilization (coolant drained) | 83-3021 | (x) | (x) | - (1) |
x: must be carried out
(x): may need to be carried out (depending on findings or variant)
(A), (B), (C): Optionally, tighten only one operation item no.
(1): In deficiency phase 3/4, a replacement of the residual heat utilization circulation pump is included for replacement of the coolant hoses (20-7480). The coolant hoses and the circulation pump for residual heat utilization are only available as a parts kit.
Overview of operation items that are related to sludging of the coolant, but affect the retarder and must be invoiced through separate damage codes: |
Scope | Operation text | Operation position no. | Phase 1 | Phase 2 | Phase 3/4 |
Checks (retarder) | Check retarder for inner leak tightness (deficiency phase determined) on veh. in deficiency phase 1 | 43-7279 | X | - | - |
Check retarder for inner leak tightness (engine cooling system flushed), vehicle with code B3H | 43-7278 | - | X | X | |
Check bolt of side channel pump (for troubleshooting on retarder), vehicle with code B3H | 43-7296 | (x) | (x) | x up to SWR 16W20 | |
Replace retarder | Remove/install/replace retarder downward (engine cooling system flushed), veh. with code B3H | 43-7268 | - | - | X |
Remove/install/replace retarder upward (engine cooling system flushed), veh. with code B3H | 43-7273 | - | - | X | |
Remove/install/replace retarder downward (after check), veh. with code B3H | 43-7269 | (x) (A) | (x) (A) | (x) | |
Remove/install/replace retarder upward (after check), veh. with code B3H | 43-7272 | (x) (B) | (x) (B) | (x) |
x: must be carried out
(x): may need to be carried out (depending on findings or variant)
(A), (B): Optionally, tighten only one operation item no.
Retarders up to manufacturing date 16W20 in phase 3/4
Retarders up to manufacturing date 16W20 must always be replaced. In addition, the screw of the retarder side channel pump must be checked to ensure that it is present (see document AR43.30-W-0054WR, operation steps 4 to 6).
Retarders as of manufacturing date 16W20 in phase 3/4
Retarders as of manufacturing date 16W20 must be checked for internal leak tightness as per AR43.30-W-0048WR. If the retarder is leaktight internally, it remains in the vehicle.
If the retarder is not leaktight internally, it must be replaced. In addition, the screw of the retarder side channel pump must be checked to ensure that it is present (see document AR43.30-W-0054WR, operation steps 4 to 6).
Referenced documents
- ah2000n000202h Notes on further operations for coolant sludging
- ar2000w1251h Flush engine cooling system