Radiator Filling for the SpecRacer GEN2 & 3

Background           

Filling the radiator of a SpecRacer requires time and patience.  A vacuum pump can speed up the process, especially with a GEN3.  Both vacuum and gravity techniques are described below.  It is important to get all of the air out of the cooling system for the cooling system to work properly.  It is possible to destroy a motor if you do not get the air out of the system before running the motor hard.  Follow this procedure any time a reasonable amount of coolant has been lost, from removing the engine or due to a leak in the system.

GEN2 or GEN3 Fill Procedure with a Vacuum Pump

Special Tools

1.         Vacuum Pump – A small vacuum pump helps remove the air in the lines of the cooling system.  Any small vacuum pump will work a pump that work well is a Grainger part number 4YD41.  You will need to buy a few hoses from your local hardware store to connect it to the water fill cap opening.

                     Vacuum Pump with Hoses Connected                                               Vacuum Hose Inserted in Tank

                     Vacuum Pump with Hoses Connected                                             Vacuum Hose Inserted in Tank

2. Initial Vacuum Step – Insert the vacuum pump hose into the top of the filler neck.  Turn on the vacuum pump for a minute or so and when you see the radiator hoses that connect to the radiator collapse then remove the vacuum.  You should see that the level of the water has dropped in the tank. 

3. Post-Vacuum Water Fill – Fill the radiator up to a point just below the filler tube.  The first time should take more water than subsequent fills.

4.  Vacuum Steps – Again hook up the vacuum and pull a vacuum for about a minute or until the hoses start to collapse.

5.  Repeat Until Full – Repeat the vacuum and fill steps until either the vacuum pump is pulling out water and/or until you do not need to add water after the vacuuming step. 

6.  Initial Engine Run-in – With the radiator cap off, start the motor.  Let the motor run for about 2 minutes.  Continue to check the water level.  If you do not have to add any water, you probably have gotten all the air out of the system.  If you did have to add some water you might want to consider using the vacuum pump a few more times.

7.   Final Engine Run-in - Once you feel, you have all of the air out of the system replace the coolant tank cap and then start and bring the motor up to operating temperature.  As the motor warms up feel the pressure in the front hoses that go to the radiator.  As some point both hoses should start to get hot, signifying the thermostat is open and the water is flowing through the system.   The hose should also start to be hard to collapse.  This is an indication that the system is becoming pressurized due to the water getting close to the boiling point.  As soon as you have hot and pressurized hoses, shut off the motor.  During this procedure, do not let the motor get too hot or above about 190.

8.  Cool Down & Check – Now let the car cool down for about 15 to 30 minutes.  USE GLOVES OR A TOWEL TO PROTECT YOUR HAND IN CASE IT IS STILL HOT ENOUGH TO BOIL.  Once you feel the system has cooled enough to check the water level you can pull the lever on the cap and remove it.  Check the water level in the tank.  If the water level is about where it was before you started the motor, you are ready for a test ride.  If the water is low, re-start the motor and slowly add water until the tank is full.  Go through this process until you are not adding water to the system.

9. Test Drive – after you feel the coolant system is full, it is a good idea to test-drive the car.  Either drive the car around the pits until it gets hot and/or ask the steward for a hardship lap.  After testing the car wait and recheck the water level and if it is the same as when you went out you should have a high confidence the cooling system is ready to race.  

GEN2 Fill Procedure without a Vacuum Pump

1.  Initial Fill - Fill the expansion tank with water until the level is just below the fill tube.  It is a good idea to use water without antifreeze.  Using water with antifreeze will create a slick track if the car leaks on the track.  If you run in an area that gets hot, consider using “Water Wetter” from Red Line Oil. Red Line claims the product provides better thermal conductivity and therefore better cooling than water.  For those of you that live in an area that freezes for reasonable periods of time you might consider adding antifreeze in the winter, draining the water, or just keep the car inside were it doesn’t go below freezing.

2.  Raise the Rear – Use a hydraulic jack to raise the rear of the car up about one foot. Leave the expansion tank cap off and start the engine.  Monitor the water level and fill it as necessary.  Let the engine run until both of the coolant tubes in the car’s side pods are hot.   The one that receives the water from the engine will get hot first.  After the thermostat opens up the other, return, tube will get hot. Having both tubes hot ensures that water is flowing through the entire system.  During this procedure, do not let the motor get too hot or above about 190.

3. Test Drive – after you feel the coolant system is full, it is a good idea to test-drive the car.  Either drive the car around the pits until it gets hot and/or ask the steward for a hardship lap.  After testing the car wait and recheck the water level and if it is the same as when you went out you should have a high confidence the cooling system is ready to race. 

GEN3 Fill Procedure without a Vacuum Pump

1.  Initial Fill - Fill the expansion tank with water until the level is just below the fill tube.  It is a good idea to use water without antifreeze.  Using water with antifreeze will create a slick track if the car leaks on the track.  If you run in an area that gets hot, consider using “Water Wetter” from Red Line Oil. Red Line claims the product provides better thermal conductivity and therefore better cooling than water.  For those of you that live in an area that freezes for reasonable periods of time you might consider adding antifreeze in the winter, draining the water, or just keep the car inside were it doesn’t go below freezing.

2.  Raise the Left Side – Use a hydraulic jack to raise the left side of the car up about a foot. Leave the expansion tank cap off and start the engine.  Monitor the water level and fill it as necessary.  This process can take some time so be patient.  During this procedure, do not let the motor get too hot or above about 190.

3.   Final Engine Run-in - Once you feel, you have all of the air out of the system replace the coolant tank cap and then start and bring the motor up to operating temperature.  As the motor warms up feel the pressure in the front hoses that go to the radiator.  As some point both hoses should start to get hot, signifying the thermostat is open and the water is flowing through the system.   The hose should also start to be hard to collapse.  This is an indication that the system is becoming pressurized due to the water getting close to the boiling point.  As soon as you have hot and pressurized hoses, shut off the motor.  During this procedure, do not let the motor get too hot or above about 190.

4.  Cool Down & Check – Now let the car cool down for about 15 to 30 minutes.  USE GLOVES OR A TOWEL TO PROTECT YOUR HAND IN CASE IT IS STILL HOT ENOUGH TO BOIL.  Once you feel the system has cooled enough to check the water level you can pull the lever on the cap and remove it.  Check the water level in the tank.  If the water level is about where it was before you started the motor, you are ready for a test ride.  If the water is low, re-start the motor and slowly add water until the tank is full.  Go through this process until you are not adding water to the system.

5. Test Drive – after you feel the coolant system is full, it is a good idea to test-drive the car.  Either drive the car around the pits until it gets hot and/or ask the steward for a hardship lap.  After testing the car wait and recheck the water level and if it is the same as when you went out you should have a high confidence the cooling system is ready to race.