Volvo Penta TAD1630G, Workshop Manual

Page: 149 / 164

Group 22 Service procedures - cooling system
147
5
Run the engine at normal operating temperature for about
10-15 minutes. This must be done thoroughly in order to
neutralize the oxalic acid.
6
Flush the system thoroughly clean according to point 3. In-
creased flushing effect can be obtained by mixing water with
air, in which case flushing must, without exception, be
carried out from bottom to top (radiator), or from the
drain cock in question on the cylinder block.
Note: Remove the filler cap from the expansion tank/radia-
tor. In the case of separate expansion tank, this should also
be flushed from the bottom and up with the filler cap removed
for efficient cleaning. Flush the heater, if fitted, with the hoses
removed to be sure that remaining deposits are removed.
7
If there is still rust and slime the cooling system, repeat the
steps under points 1–6.
When cleaning, check that all hoses are free from defects.
Replace if necessary.
8
Fill the system with a coolant recommended by Volvo Penta.
See section “Coolant”. Check to make sure that there are no
leaks.
Cooling system, pressure-
testing
Special tools: 999 6662, 998 9860 with compressed air and
999 6433. Or use standard pressure testing gear.
Checking pressure-testing device 999
6662
Before using the pressure-testing equipment it must be
checked as follows:
A
Check that the knob on the relief valve (A) is fully opened
and connect the test device to the compressed air system.
Open cock (B) and adjust the relief valve until a pressure of
100 kPa (14.5 psi.) is indicated on the gauge.
Note: The relief valve’s knob can be locked by moving the
locking ring axially.
Note: Always follow applicable safety regulations.
B
Close cock (B). The pressure must not drop during two min-
utes if the test device is to be considered reliable.
Pressure testing
1
Remove the coolant filler cap and instead fit cap 999 6433 on
the radiator. Plug the connection to an extra plastic expan-
sion tank, if fitted, during the pressure- testing.
2
Ensure that the knob on the relief valve (A) is fully opened
and connect the hose from the pressure-testing device to the
cap 999 6433.
3
Seal the drain line from the filler pipe.
4
Connect the pressure-testing device 999 6662 to the com-
pressed air system and open the cock (B).