Submitted by Roy Cail.

Did you ever say the following:  My engine continues to overheat. We have put on a new water pump, the radiator was “cleaned and soldered and filled”, but it still overheats.  Not an abnormal thing, especially in the Oklahoma summers.

First lets define overheating…..is it steaming or just pumping water out the top?…. If it just pumping water out you may be over filling it….let the radiator find its own level… each “A” seems to have its own level.  As an example, in Kansas City I added water to our 1929 all the way to the top — I knew it was too full but it sure looked good!!  When I started the car it promptly pumped out the excess water until it reached its normal operating level.

Suggestions:

There are several things that can cause a Model A to overheat.  The main cause is usually the radiator.  First you can check to see if your radiator has 3 rows of tubes.  Some of the older replacement radiators had only 2 rows.  That will not provide sufficient cooling.  If the radiator is old and has been in the car a long time, the fins of the radiator become loose and cannot dissipate the heat.  Also, if the radiator is old and has been in the car a long time, calcium deposits in the radiator will reduce the cooling efficiency of the radiator.

Like many Model A owners we had to replace a radiator as once we got the car over 40 MPH it would get hot.  The radiator had 3 tubes but only 6 fins per inch (normal) plus the flow rate was quite slow.  The new core that was put on has 12 fins per inch plus they are crinkled to provide maximum cooling surface area.  Replacing the radiator along with slowing the rate of flow (installed a Thermostat) stopped the overheating on our “A”.

Now let’s consider other potential causes of overheating.  First make sure the timing is set correctly.  Then make sure nothing is blocking the front of the radiator, like a license plate.  If you have a new engine, it will sometimes run hot until it is broken in. There are several books and articles that have been written that will tell how to correctly set the timing.  A blown head gasket can also cause overheating.  Check for bubbles in the water at the filler neck.  This may indicate a blown head gasket.  Running your car too lean (Gas Adjustment Valve, GAV) can also contribute to your motor running hot.  In this hot weather there can be many contributing factors.