Honda Civic Radiator Overflow Tank
How to Diagnose Problems with the Honda Civic Radiator Overflow Tank
The overflow tank is an important part of a car's cooling system. It stores any extra coolant overflowing from a hot radiator. As the radiator cools down, the coolant inside it will contract, creating a vacuum that sucks the coolant in the overflow tank back into the radiator. This ensures that no coolant is wasted and that your radiator won't be left dry. Unfortunately, problems may occur with the overflow tank, and they need to be fixed immediately. To help you out, here are some common Honda Civic radiator tank problems you should know of:
Significant decrease in coolant level
If you find yourself adding coolant to the overflow tank often, you may have a leak in the cooling system. Check the overflow tank first for any sign of damage. If the overflow tank is in excellent condition, the leak may be from the radiator, the coolant hoses, or within the engine. Survey the bottom of the Civic and check if there is any puddle of coolant. If you see such puddle, the source of the leak could be directly above it. Trace the source of the leak and apply the appropriate fix.
Damaged overflow tank
Damage to the overflow tank should be fixed immediately. Inspect the overflow tank before doing anything; if the damage is relatively small, trying using plastic or epoxy welds to seal it shut. Be sure to follow manufacturer instructions closely and give the epoxy time to cure and dry up before reinstalling the overflow tank. If the overflow tank is old, then the damage is probably caused by wear. Replace the whole tank in that case. Remember that any fix you might try on an old overflow tank will only be temporary; chances are, it will break again in the near future. For extensive damage, replacing the whole thing should be a no brainer.
Coolant not being sucked in from the overflow tank
You can check for this condition by inspecting the coolant level in the radiator. Be sure to check your radiator after the Civic's engine has thoroughly cooled down. If there is a decrease in the radiator's coolant level even if the coolant in the overflow tank is left untouched, then air must be getting in the radiator from some other point. The first thing you should check is the radiator cap. Replace it with a new one and see if that solves the problem. Check the hose connecting the overflow tank to the radiator and be sure that no leak is present. Other parts you should also check are the rest of the cooling system hoses and the radiator.