Blue Bird Coachworks 450 LXi, Owner'S Manual

Page: 479 / 684

5-3 Engine Maintenance
450 LXi Owner Manual
~ 5-3-20 ~
Rev. “C”
5-3.19.2 Add the SCA, If Necessary
Slowly loosen the cooling system fi ller cap in order to relieve the pressure. Remove the cooling system fi ller cap.
If necessary, drain some coolant from the cooling system into a suitable container in order to allow space for the extra SCA.
Add the proper amount of SCA.
Clean the cooling system fi ller cap. Inspect the gaskets of the cooling system fi ller cap. If the gaskets are damaged,
replace the old cooling system fi ller cap with a new cooling system fi ller cap. Install the cooling system fi ller cap.
1.
2.
3.
5-3.20 Cooling System Water Temperature Regulator - Replace
Replace the water temperature regulator before the water temperature regulator fails. This is a recommended preventive
maintenance practice. Replacing the water temperature regulator reduces the chances for unscheduled downtime.
A water temperature regulator that fails in a partially opened position can cause overheating or overcooling of the engine.
A water temperature regulator that fails in the closed position can cause excessive overheating. Excessive overheating could
result in cracking of the cylinder head or piston seize problems.
A water temperature regulator that fails in the open position will cause the engine operating temperature to be too low during
partial load operation. Low engine operating temperatures during partial loads could cause an excessive carbon buildup
inside the cylinders. This excessive carbon buildup could result in an accelerated wear of the piston rings and wear of the
cylinder liner.
Consult your Caterpillar dealer for the replacement procedure of the water temperature regulator.
WARNING!!
Pressurized System
- Hot coolant can cause serious burns. To open the cooling system fi ller cap,
stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap
slowly in order to relieve the pressure.
NOTICE: Do not exceed the recommended amount of supplemental coolant additive concentration. Excessive
supplemental coolant additive concentration can form deposits on the higher temperature surfaces of the cooling
system, reducing the engine’s heat transfer characteristics. Reduced heat transfer could cause cracking of the
cylinder head and other high temperature components. Excessive supplemental coolant additive concentration could
also result in radiator tube blockage, overheating, and/or accelerated water pump seal wear. Never use both liquid
supplemental coolant additive and the spin-on element (if equipped) at the same time. The use of those additives
together could result in supplemental coolant additive concentration exceeding the recommended maximum.
NOTE: Always discard drained fl uids according to local regulations.
NOTICE: Failure to replace your water temperature regulator on a regularly scheduled basis could cause severe
engine damage.
Caterpillar engines incorporate a shut design cooling system and require operating the engine with a water
temperature regulator installed.
If the water temperature regulator is installed incorrectly, the engine may overheat, causing cylinder head damage.
Ensure that the new water temperature regulator is installed in the original position. Ensure that the water
temperature regulator vent hole is open.
Do not use liquid gasket material on the gasket or cylinder head surface.
NOTE: If only the water temperature regulators are replaced, drain the coolant from the cooling system to a level
that is below the water temperature regulator housing.