QuestionI have an 86 Honda VT700C. After riding it this evening, it was sitting in the driveway idling and all of a sudden the lower radiator hose blew off the radiator. The temp guage had not even made it up to normal riding temp yet. Any ideas on what may have caused this. Thanks in advance for any help.
AnswerHi Jon,
Cooling systems generate pressure even at low temperatures.
A loose hose connector, defective/weak hose, or internal obstruction may have caused the lower hose to blow.
Inspect the hose, clamp, and hose fitting for evidence defects, etc...
Have the cooling system pressure tested.
Respectfully,
Mark Shively
Coolant Overheating & Servicing
By Mark Shively
Motorcycle and ATV cooling systems are air-free by design. Air in the cooling system lowers the boiling point of coolant to just above the point of which water boils and causes engine overheating.
Air enters the cooling system anytime the system is opened by changing the coolant, replacing the thermostat, temperature sensor, fan switch, or when other repairs requires draining coolant.
It is important to purge air from the system after servicing. The exceptions to this are opening the radiator cap or coolant reservoir cap for routine inspection and periodic maintenance.
The Mityvac Company manufactures a tool for purging air from cooling systems. The tool is the AirEvac tool. The Mityvac Cooling System AirEvac Kit refills cooling systems in minutes without trapping air that can cause overheating. The kit combines a universal adapter with a compressed-air-operated Venturi vacuum to quickly eliminate trapped air by purging and refilling the cooling system under vacuum.
The result is an air-free cooling system. Higher coolant boiling temperatures ensures a cool running engine and optimum performance.
