5 Cooling System
DETROIT DIESEL 53
the seal or hose is in its proper position before tightening
10. Install the engine thermostats.
the clamps. All external leaks should be corrected as
soon as detected.
11. Close all of the drains and refill the engine with fresh
The fan belt must be checked and adjusted, if
necessary, to provide the proper tension and the fan
shroud must be tight against the radiator core to prevent
recirculation of air which may lower the cooling
When the engine lubricating system has been
contaminated by an ethylene glycol antifreeze solution
or other soluble material, the following cleaning
procedure, using Butyl Cellosolve, or equivalent, is
When the engine cooling or lubricating system becomes
contaminated, it should be flushed thoroughly to remove
CAUTION: Use extreme care in the
handling of these chemicals to
prevent serious injury to the person
that is damaging to the engine if it is not corrected
or damage to finished surfaces.
immediately, is a cracked oil cooler core. With a
Wash off spilled fluid immediately
cracked oil cooler core, oil will be forced into the cooling
with clean water.
system while the engine is operating, and when it is
If the engine is still in running condition, proceed as
stopped, coolant will leak into the lubricating system.
Coolant contamination of the lubricating system is
1. Drain all of the lubricating oil.
especially harmful to engines during the cold season
when the cooling system is normally filled with an
2. Remove and discard the oil filter element. Clean
ethylene glycol antifreeze solution. If mixed with the oil
and dry the filter shell and replace the element.
in the crankcase, this antifreeze forms a varnish which
quickly immobilizes moving engine parts.
3. Mix two parts of Butyl Cellosolve, or equivalent, with
one part SAE 10 engine oil. Fill the engine crankcase to
the proper operating level with the mixture.
cooling system and the lubrication system must be
thoroughly flushed as follows:
4. Start and run the engine at a fast idle (1,000 to
1,200 rpm) for 30 minutes to one hour. Check the oil
If the engine has had a failure resulting in the
5. After the specified time, stop the engine and
immediately drain the crankcase and the filter.
the following procedure is recommended.
Sufficient time must be allowed to drain all of the fluid.
1. Prepare a mixture of Calgon, or equivalent, and
6. Refill the crankcase with SAE 10 oil after the drain
water at the rate of two ounces (dry measure) to one
plugs are replaced, and run the engine at the same fast
gallon of water.
idle for ten or fifteen minute-sand again drain the oil
2. Remove the engine thermostats to permit the
Calgon and water mixture to circulate through the
7. Remove and discard the oil filter element, clean the
engine and the radiator or heat exchanger.
filter shell and install a new element.
3. Fill the cooling system with the Calgon solution.
8. Replace the drains and fill the crankcase to the
proper level with the oil recommended for normal
4. Run the engine for five minutes.
5. Drain the cooling system.
9. To test the effectiveness of the cleaning procedure,
it is recommended that the engine be started and run at
6. Repeat Steps 3 through 5.
a fast idle (1,000 to 1,200 rpm) for approximately 30
minutes. Then stop and immediately restart the
7. Fill the cooling system with clean water.
8. Let the engine run five minutes.
9. Drain the cooling system completely.
1972 General Motors Corp.