MAS002324

AfterSales BOL Technical Information
MAS002324
(BOL 20-12)
From: Aftersales – TSO
To: Maserati Network
Auburn Hills, MI | September 28, 2020
Engine coolant leaks from the cabin heater water delivery
hose or the cabin heater water return hose
Section: 01.71 - 4 COOLING SYSTEM: NOURICE AND LINES
Models: M156, M157, M161 from MY18 up to and including MY20
Issue: High engine coolant temperature indication on IPC (as figure 1) or engine coolant leak
Figure 1
Cause: Engine coolant leaking from the cabin heater water delivery hose or the cabin heater
water return hose
Action: Pressurize the engine coolant system to find the leak. If the cause of the leak is the
cabin heater water delivery hose or the cabin heater water return hose (Figure 2), open a BOL
as a “Support Request” and attach:
•
•
DTC and parameters report from the ECM
Photos of the leak and the hoses as they are installed in the car (as in figure 2)
Then proceed to remove the leaking hose. Avoid touching the inside of the hoses in order
not to damage any of the components.
Figure 2
•
Photos of flared end of the pipe on heater side (as figures 3,4 and 5)
Figure 3
Figure 4
Figure 5
•
photos of the hoses removed, with the detail of all damaged areas (as figures 6 and 7)
Figure 6
Figure 7
•
photos of the markings on the cabin heater water delivery hose or the cabin heater
water return hose (as figures 8 and 9)
Figure 8
•
Figure 9
photos of the securing clamps of the hoses on the cabin heater, with a clear indication
of the markings on the clamps (as figure 10)
Figura 10: collar markings
After the replacement of the damaged hose(s) and the securing clamp(s) on the cabin heater
side, perform a road test to verify the performance of the engine cooling system.
Conclusions: Please keep all replaced components (including the securing clamps), if the
parts are requested by Maserati Warranty.