MTU 20V4000M93 series Operating Instructions Manual page 234

Filling with coolant through filler neck
1. Fill coolant through filler neck on expansion tank until coolant emerges from the loosened unions at the cool-
ant distributor.
2. Tighten the union for coolant line at the coolant distributor (→ Page 224).
3. Continue to fill until coolant level remains constant at top edge of filler neck.
4. Tighten the coolant line union on both turbochargers (→ Page 224).
5. Check satisfactory condition of breather valve and clean sealing faces if required.
6. Start engine with open expansion tank (→ Page 76) and operate it at idle.
7. Open vent points successively, starting at the lowest point and proceeding upwards. Wait until air no longer
emerges from the vent points and close them.
8. Top up coolant in expansion tank until coolant level is at the overflow edge.
9. When coolant temperature is 40 °C (T-Coolant), increase engine speed to 1,000 rpm for approx. 2 minutes.
With the engine running idle, top up the expansion tank with coolant until coolant level is at the overflow
edge.
10. Start engine with open expansion tank and run it up to nominal speed (full load).
11. Operate engine at idle for approx. 5 minutes until coolant temperature is steady. Check coolant level in ex-
pansion tank. If coolant level is above 50%, close filler neck cover. If the coolant level in expansion tank is
less than 50%, stop engine (→ Page 88) and fill coolant into expansion tank until coolant level is at the over-
flow edge.
12. Close breather valve on expansion tank and briefly run up engine to full load.
13. Stop engine (→ Page 88).
14. Allow the engine to cool down, then top up with coolant until coolant level is at the overflow edge. Close
breather valve on expansion tank.
232 | Coolant Circuit, General, High-Temperature Circuit | MS150048/05E 2018-03