Filling the SRF Cooling System |
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Background | ||
Several recent events have prompted me to post this summary of filling the cooling system on the SRF. It is possible to destroy the motor if you dont pay attention to this process (--been there, done that-- it sucks). The process below has worked well for us and is basically the instruction that comes with my coolant expansion tank. Note that you should follow this procedure any time the coolant has been drained from the cylinder head...even if you dont drain the whole system. | ||
The Process | ||
While filling the coolant system is relatively straight forward, a few notes are
in order. The SRF cooling system is a closed system -- there is no overflow.
When the coolant is heated by the engine, it expands and the purpose of the
expansion tank is to provide some air space (at the highest point of the system) for the
coolant to expand into. With this in mind, never completely fill the expansion tank
(except for the first filling) -- you need to leave some air space. Typically, you want to
fill the expansion tank half way -- although you dont need to be precise as long as
there is an airspace. The specific steps for filling the system with coolant are below: |
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1) | Fill the system with coolant for the first time. Fill the expansion tank completely full. While the Roush/Ford Spec Racer Installation Instructions, step 20 suggest a 50/50 mix of water and antifreeze, we recommend against the use of antifreeze for two reasons: a) if you develop a leak, antifreeze on the track is a LOT slipperier than water -- making it harder for you and your competitors to control your cars when driving through your dropped fluids and b) we believe that water and the Red Line Oil product Water Wetter provide better thermal conductivity than water and antifreeze. Just be sure to drain the system in the winter if you live in an area where the temperature drops below freezing. Ford will not warranty engines cracked from frozen coolant. | |
2) | Raise the rear end of the car with a quick jack. Again, in contrast to the Roush/Ford Spec Racer Installation Instructions, step 20 we strongly suggest you DO NOT raise the front of the car and open the radiator. We believe raising the front end of the car is a good way to induce air pockets since other parts of the system are higher than the radiator. | |
3) | With the expansion tank cap in place, but very loose (so air can enter), start the engine. Let the engine run until BOTH coolant tubes in the cars side pods are hot. Note that if you are breaking in a new engine, you should NOT let the car just idle until you reach temperature. See Dave Liddles article in the SpeX Files on this site for more info. You will find that one tube will get hot pretty quickly, but the other tube remains cold. Having both tubes hot ensures that water is flowing through the entire system. During this procedure dont let the motor overheat (dont exceed 210-215 degrees). | |
4) | Shut off the motor, remove the expansion tank cap and let the motor completely cool. | |
5) | After the motor has cooled, you should be able to add about 1 to 2 quarts of coolant to bring the expansion tank back to half full. Note that total fill capacity of the SRF is approximately 10 quarts. | |
6) | Put the tank cap on tightly. | |
Rev. 3/5/98 |