Re: 1929 coolant issue

Posted by TxGoat On 2024/2/15 10:34:39

Your water pump may be leaking at the seal. It is possible for a water pump to leak air in at the seal when the engine is running. This will tend to form air and steam pockets in the water jacket and displace coolant out the overflow. The water pump can have this condition and yet not leak when the engine is stopped, or it may drip coolant.

The solution is to tighten the packing just slightly, assuming the seal is in good condition and properly lubricated. A water pump with worn bushings won't allow the seal to work as it should, and it can be expected to leak air in and coolant out.

An excessively tight fan belt can also cause problems.
A new pump or newly rebuilt pump ought to be run for an hour or so with the belt a little loose to allow bearings and the seal to seat. The seal may require one or two adjustments at first. Usually, 1/4 to 1/2 turn of the packing nut will be enough. Too tight will cause the seal to fail.

A pinhole leak in the lower radiator hose or in the core itself can have allow air to be pulled into the system, though the pump is the more likely culprit.

A leaking head gasket can also cause excess coolant displacement. Was the head re-torquing procedure followed?

Some coolant expansion is normal, but it should not cause the core to be exposed after running and stopping the engine. A radiator filled to the brim when cold should not expel much more than a pint or two of coolant at operating temperature.