MWM MS 3.9L, Operation And Maintenance Manual, Page: 29 / 53

27
NP 085.70.69 - 01/06
Engine Coolant Refilling
After draining the cooling circuit, follow the instructions from section "Refilling"
for refilling the system with engine coolant.
Coolant nozzle cap
The cap controls the cooling system's internal pressure by means of its relief
and depressor valve. If it is necessary to remove the cap while the engine is
hot, turn it until its first step for internal pressure relieving before its removal.
In case it is defective, never try to fix it, but replace it for a new one instead.
Caution: Never operate an engine with the coolant cap
removed. Never improvise another type of cap.