How should an operator check for a pinhole leak in a pressurized hydraulic hose?
- Run a bare hand slowly along the hose
- Pass a piece of cardboard or wood along the hose
- Wrap a rag around the hose and squeeze
- Hold a gloved hand close to the hose to feel for spray
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B. Pass a piece of cardboard or wood along the hose
A fine jet of hydraulic oil can pierce skin and gloves and cause a serious injection injury, so a piece of cardboard or wood is used to find the leak. A leather or cloth glove does not stop high-pressure oil.
Reference: NCCER Heavy Equipment Operations Level 1, Heavy Equipment Safety
Why should the radiator cap never be removed from a hot engine?
- Cold air rushing in can crack the hot cylinder block
- Pressurized coolant can spray out and cause burns
- The thermostat will stick in the open position
- The water pump will lose its prime and fail
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B. Pressurized coolant can spray out and cause burns
A hot cooling system is under pressure, and releasing the cap lets scalding coolant and steam erupt. The level is checked at the overflow tank or after the engine has cooled.
Reference: NCCER Heavy Equipment Operations Level 1, Heavy Equipment Safety
What is the correct condition for checking the engine oil level on most machines?
- Machine level with the engine at high idle
- Machine facing uphill with the engine off
- Machine parked with the blade raised
- Machine level with the engine stopped
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D. Machine level with the engine stopped
Parking on level ground and stopping the engine lets the oil drain back to the pan so the dipstick reads true. A running engine holds oil up in the galleries and gives a false low reading.
Reference: NCCER Heavy Equipment Operations Level 1, Basic Operational Techniques