Step by step guide on how to find and repair an engine coolant leak. This article
pertains to all vehicles other then electric.
Difficulty Scale: 4 of 10
Tools and Supplies Needed
- Screwdriver set
- Wrench set
- Protective eye wear and gloves.
- Fluid catch basin
Begin with the car on level ground, engine off (cold) with the parking brake
- To confirm an engine coolant leak inspect
reservoir tank, if the reservoir is empty the cooling system probably has a leak.
Always check the coolant level when the engine is cold.
Radiator Cap and Coolant Reservoir
- Some times by simple inspection a coolant
can be discovered using a flashlight to go over all key points such as the radiator,
water pump, hoses, heater control valve and heater core. Visit -
Radiator Coolant Leak
- If no coolant leaks are easily apparent
a radiator pressure tester is needed. This device is securely held into the radiator
cap inlet port while allowing a pressure pump to fill the system with pressure to
help force the leak into view.
- Once this inspection is complete and still
no leaks are found, remove the oil fill cap to check for a blown head gasket. This
is done by inspecting the oil inside the cap for a yellowish colored goop. Next,
remove the oil dipstick to and inspect the integrity of the motor oil. If this oil
is white or yellow coolant is leaking internally into the engine, in this case dis-assembly
is required. Visit -
in motor oil
- Next, the car heater core must be inspected;
the quickest way to check the heater core condition without removal the heater core is to inspect the passenger's
side foot well compartment carpet for the presences of coolant. If coolant is present
the heater core has failed and must be replaced or repaired. After necessary repairs
have been made refill the cooling system with manufacturers recommended engine coolant
and recheck operation.
Many points in a cooling system are able to develop leaks. Understanding the
main physical components of the system helps. A leak in the heater core most often
results in coolant on the front passenger-side floor. Most automobile antifreeze
are either green, red, blue or yellow which are very toxic. Care must be taken when
disposing of old coolant, the sweet odor can attract children and pets.
When removing the old hoses be careful to not apply excess force to fragile components
such as the radiator and heater core. Often cutting old coolant hoses vertically
along the connection helps in the removal process.
- To avoid cooling system problems change engine coolant on a regular basis
(30k to 40k) to avoid a chemical decomposition which will create an acid that
attaches cooling system components and gaskets. Visit -
Engine coolant service, Visit -
- Always check coolant level when the vehicle is cold.
- When checking coolant hoses for replacement, squeeze each hose firmly, they
should feel soft and flexible. If hoses are brittle or cracking replacement
- Inspect hoses or irregular bulges which are signs of a potential failure.
Article first published 2016-11-26