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forpsych 11/17/2019

2007 Honda Civic LX 4 Cyl 1.80L


can leaving the cap off the coolant reservoir container (not the radiator) = radiator losing coolant, and overheating?

A garage that performed work on my vehicle has told me that them leaving the cap off the coolant reservoir container (not the radiator itself) would not result in the radiator losing coolant, and eventually overheating, which mine did, 8 days later. This is in a 2007 Honda Civic, and the cap has a tube built in which comes directly from the radiator. This then lead to my engine block cracking (which a service bulletin warns about when this engine overheats).
Could you please respond to whether or not this would be possible and/or likely IF the cap where left off the coolant reservoir container?

1 Answer


Jimm 11/18/2019

Yes, it is possible - especially within 8 days. The simple reason is the cooling system must remain under pressure in order to raise the boiling point of the anti-freeze / water mixture known as coolant.

Without the reservoir container cap - the cooling system cannot develop the pressure needed, so it's possible the damage was as result of the reservoir cap being left off.
Leaving the plastic cap off of the plastic overflow reservoir may cause coolant loss if the overflow pick-up tube is blocked or pinched.


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