Volvo Penta TAD1630G, Workshop Manual

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Service procedures - cooling system Group 22
146
4
Start the engine.
5
Drive belts, adjusting
Replace belts which have become oily, worn or damaged in
any way.
Note: Belts that work in pairs should always be replaced at
the same time.
Tension the alternator belts after loosening the alternator.
Correct tension is obtained when the belts can be de-
pressed about 10 mm (0.400") midway between the pul-
leys.
The engine is equipped with an automatic belt tensioner for
the fan belts.
Cooling system, cleaning
The cooling system (including the charge air cooler on
TWD1630) should be cleaned when replacing the coolant.
It is generally sufficient to flush through with clean water. If
the cooling system has large rust and mud deposits we rec-
ommend the following cleaning method:
1
Empty and flush the system clean. Use Volvo radiator
cleaning kit, part no 1141658, or dissolve 1 kg (2.2 lbs) of
oxalic acid* in 5 liter (5.3 qt) hot water and pour the mixture
into the cooling system. Top up with clean water.
* Not marketed by Volvo Penta, can be purchased from chemical
stores.
Chemical formula for oxalic acid: C
2
H
2
O
4
.
Chemical formula for sodium hydrogen carbonate: NaHCO
3
.
WARNING! Protect hands and face. Oxalic acid is
poisonous and hazardous to the skin.
2
Run the engine until it reaches normal operating tempera-
ture and then for about another 2 hours.
Note: Any heater controls must be set to “hot”.
3
Drain the system and flush out immediately and thoroughly
with clean water. For this purpose the thermostat housing
(thermostat), upper and lower radiator hoses, drain cocks
and plugs should be removed to give the best possible
draining speed. Do not forget the engine heater or heater el-
ement, if fitted. Continue flushing until the water coming out
is clean. It is essential to remove all oxalic acid, otherwise
the remains can increase the risk of further corrosion.
4
Dissolve 200 grams (7 oz.) of bicarbonate* (sodium hydro-
gen carbonate) in 5 liters (5.3 qt) of water an pour into the
cooling system. Top up with clean water.
Note: Never use soda (sodium carbonate Na
2
CO
3
) as in-
correct handling can result in severe corrosion damage.
Checking radiator and charge
air cooler
Should higher than normal coolant temperatures be observed,
the passage of air through the charge air cooler and radiator
(TAD1630/ TAD1631) must always be checked.
Check that the external cooling sections of the radiator and
the charge air cooler are not blocked by insects or other im-
purities that can restrict the air flow. If obstructions are found
use a mild grease- dissolving detergent and water. Never
use water at high pressure or compressed air.
Straighten out any bent cells in the cell system. Flush the ra-
diator from the front. In cases of more serious blockage the
radiator must be removed entirely and then cleaned with a
mild detergent. Also check that the fan cover has not come
loose or is leaking in any other way.
Also check that the fan cover and, if fitted, the sealing strip
fitted between the fan cover and the charge air cooler has not
come loose or is leaking in any other way.
Connect a wire between the engine body and the level
switch.
6
Alarm and/or automatic stop should be triggered after 4 sec-
onds.
Coolant leakage
Loss of coolant can occur in two ways:
– Loss of coolant during running
– Loss of coolant after stopping a hot engine
Coolant loss during running can be due to leaks in the cooling
system or air or combustion gases being pressed into the
cooling system causing the coolant to be forced through the
pressure valve. The fault can be in the compressed air com-
pressor, it fitted, or leakage at the cylinder head gaskets.
Loss of coolant after stopping a hot engine is generally due to
a faulty pressure valve (filler cap).