Radiator Pressure Cap; Radiator And Fan Shroud; Radiator Pressure Cap - Typical; Description - Mercedes-Benz 2005 Sprinter Service Manual

7 - 18 ENGINE
RADIATOR (Continued)
Fig. 10 RADIATOR AND FAN SHROUD
1 - CLIP
2 - SHROUD
3 - RADIATOR
4 - BOTTOM RADIATOR TRIM PANEL
5 - CHARGE AIR COOLER
6 - TOP RADIATOR TRIM PANEL
7 - POWER STEERING COOLER LOOP
(16) Install A/C condenser.
(17) Install front bumper.
(18) Install front end cross member.
(19) Refill power steering to proper level.
(20) Refill transmission to proper level.
(21) Close radiator drain plug and refill the cooling
system to the correct level with the appropriate cool-
ant mixture.
(22) Recharge air conditioning.
(23) Run engine until warm and check for leaks.

RADIATOR PRESSURE CAP

DESCRIPTION

All vehicles are equipped with a pressure cap (Fig.
11). This cap releases pressure at some point within
a range of 124-to-145 kPa (18-to-21 psi). The pres-
sure relief point (in pounds) is engraved on top of the
cap
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap contains a spring-
loaded pressure relief valve. This valve opens when
system pressure reaches the release range of 124-to-
145 kPa (18-to-21 psi).
A rubber gasket seals the radiator filler neck. This
is done to maintain vacuum during coolant cool-down
and to prevent leakage when system is under pres-
sure.
Fig. 11 Radiator Pressure Cap - Typical
1 - FILLER NECK SEAL
2 - VACUUM VENT VALVE
3 - PRESSURE RATING
4 - PRESSURE VALVE

OPERATION

A vent valve in the center of the cap will remain
shut as long as the cooling system is pressurized. As
the coolant cools, it contracts and creates a vacuum
in cooling system. This causes the vacuum valve to
open and coolant in reserve/overflow tank to be
drawn through connecting hose into radiator. If the
vacuum valve is stuck shut, or overflow hose is
kinked, radiator hoses will collapse on cool-down.
VA