Do not add cold water to a hot engine when
it is not running.
Rapid cooling of an
overheated engine will cause severe damage to
the cylinder head and block. To cool an
overheated engine down, leave the engine
running and add water slowly. Watch for the
steam that may be produced when adding water.
Should a radiator hose burst, secure the engine
before the temperature gets too high.
Oil Pressure Gauge
The oil pressure indicator is one of, if not, the most
important gauges to watch. Every vehicle or equipment
has an oil pressure warning light or a gauge. Should you
start to lose oil pressure and the warning light comes on,
secure the engine immediately. Operating equipment
without proper oil pressure causes severe damage to the
Check the oil level in the engine. If the oil level
is low, add oil until it is at the proper level. Start the
engine; if oil pressure does not register on the gauge
or the light stays on for 30 seconds, secure the engine.
Then document and report the problem.
Should the oil level be correct and no pressure
registers on the gauge or the warning light stays on,
secure the engine. Then document and report the
NOTE: A rule of thumb is that after starting an
engine, the oil pressure gauge should show 30 pounds
of oil pressure after the engine runs for 30 seconds.
Should the oil level be correct but no pressure
registers on the gauge, secure the engine. Then
document and report the problem.
Air Pressure Gauge
There is an air pressure gauge on each vehicle
equipped with an air-brake system. The air pressure
must be maintained within a range of 100 pounds per
square inch (psi) to 120 psi. A warning light or buzzer
should come on if the air pressure drops below 60 psi.
If there is a rapid loss of air pressure, an air unit may
have burst. A slow leak may sometimes be repaired by
tightening a fitting.
Do not operate any equipment with air
brakes if there is an air leak.
With the engine at operating rpm, the air pressure
system should build from 85 to 100 psi within 45
seconds in dual-air systems. In single-air systems
(pre-1975), the pressure should build up from 50 to 90
psi within 3 minutes.
Hydraulic Pressure Gauge
Most types of construction equipment are
equipped with hydraulic pressure guages. When
operating this equipment, you must watch for leaks.
Consult the operators manual for the pressure at
which the equipment should be operated. Should the
pressure not reach the operating range or should you
detect a leak, be sure to document and report either or
Hydraulic Temperature Gauge
Most types of construction equipment are also
equipped with hydraulic temperature gauges. In most
cases, if the hydraulic temperature exceeds the
recommended temperature, it is because the fluid
level is 100 low.
Should the fluid level be correct and the
equipment overheats, you are overworking the
hydraulic system. Stop your machine and check the
hydraulic fluid level.
Be careful because the
hydraulic fluid is hot and the hydraulic system may
be pressurized. If the fluid level is normal, let the
machine sit at idle to cool the hydraulics.
Fuel Level Gauge
When prestart inspecting a piece of equipment,
you should visually check the fuel. During the day,
watch the fuel gauge to ensure it shows a slow
depletion of fuel. Should the fuel gauge not move
in a reasonable amount of time, assume the fuel
gauge is broken.
In this case, check the fuel
visually from time to time to ensure that you do not
run out of fuel.
Hydraulic systems on equipment are used to
transmit power for steering and controlling the operation
of mechanical components. The basic components of a