Since 1952
America's Oldest Speed Shop ®
Speedway Motors Bill Smith

Get Email Deals

Join now for email specials and news

Sign Up for Special Email Offers

Congratulations! You’re now on the Speedway Motors e-mail list and will start getting new product information and offers.

Look in your inbox for an exclusive offer just for new email subscribers!

For a more personalized email experience please tell us more about yourself and your car.

Update Email Preferences

Use the following form to update your email preferences. For a more personalized email experience be sure to tell us more about yourself and your car.

Sign Up for Special Email Offers

Sign up to the Speedway Motors e-mail list to start getting new product information and offers.

Exclusive offers will arive in your inbox just for new subscribers!

For a more personalized email experience please tell us more about yourself and your car.

* Required Fields
Retype Email
First Name
Last Name
Select Country

Tell us about your interests...

To help us bring you the most relevant offers and updates, please let us know what your passions are.

Garage Sale Specials
Special deals on select race and street products.

Circle Track
Keep on track with specials on quality parts for modifieds, hobby stocks & other stock car classes.

Sprint & Midget
Specials on products for sprint cars, midgets and mini sprints.

Street Rod
Stay informed about specials on our street rod and muscle car products.

T Bucket
Product news and specials on T-Bucket kits and accessories.

Gearhead Apparel & Gifts
Show off your gearhead pride with apparel and gift items.

Muscle Car
Specials on our expanding line of muscle car parts & accessories.

To ensure email deliverability please add to your safe sender list.

Order a Free Catalog

Click here to request
one of Speedway's FREE catalogs!

Order a free catalog

Here to Help You

To speak with a knowledgeable rep,
Call: 800.979.0122
Order Line (CST)
7am - 10pm - Every Day!
Race and Rod Tech Support
M-Fri 8am - 5pm
Customer Service
M-Fri 8am - 5pm
International Customers Call:


Click Here to read what other customers have to say about us!

Visit the Museum of American Speed

"... the very best racing museum in the country." Click Here

Cooling System Principles


The purpose of your cooling system is to allow the engine to warm up to the required operating temperature as rapidly as possible and continue to maintain that temperature under all driving conditions. The cooling system should be able to do this when ambient temperature is as low as -30*F and as high as 110*F.

The peak combustion temperatures on an engine cycle can range from 4000*F to 6000*F and average between 1200*F and 1700*F. Continued temperatures as high as this would damage or weaken engine parts if the heat were not removed.

In a conventional cooling system the coolant flows through the block first, through the heads, then after the thermostat opens, through the Radiator. Low-temperature coolant leaves the radiator from the outlet and is then pumped back through the engine block where it absorbs heat and continues to re-circulate.

The coolant temperature will increase as much as 15*F as it passes through the engine, and then cools back down as it continues to cycle through the radiator. The flow rate may be as high as one gallon per minute per horsepower depending on your water pump and pulley ratio.



The thermostat's function is to control the minimum operating temperature of your engine. It’s typically designed as an encapsulated wax-based, plastic pellet heat sensor that will swell as heat increases. The temperature rating on the thermostat will indicate the temperature at which it should begin to open. Typically it’s fully open 20*F higher than its rated temperature. For example: a thermostat rated at 180*F is fully open at 200*F.


expansion tank

The cooling system is pressurized in order to raise the boiling point of the coolant. The boiling point will increase by about 3*F for each pound of increase in pressure. At atmospheric pressure, water will boil at 212*F. Under 15psi, water will then boil at 257*F. With the proper antifreeze/water mixture, the boiling point should exceed 270*F when under 15psi of pressure.


Excess pressure usually forces some coolant from the radiator through an overflow. Most systems connect the overflow to a plastic or steel reservoir to hold excess coolant when the system is hot. When the system cools, the pressure decreases and a partial vacuum forms. This vacuum will then pull the coolant from the overflow back into the cooling system, keeping the system full.


If you notice your radiator hose is collapsed when your engine cools, don’t assume the hose is bad. The collapsed hose may be a result of a defective radiator cap. A properly operating cap should draw coolant from the radiator overflow container back into the radiator and not form a vacuum in the system. We also suggest using a spring inside the lower radiator hose to prevent any chance of this happening.


You can check for proper coolant mixture by using a coolant hydrometer, supplied at most any local auto parts stores. This will measure the density of the coolant, which in turn measures the boiling and freezing point of your coolant. The higher the density, the more concentration of antifreeze to water.

It’s recommended to use distilled or de-ionized water with your coolant mix. That fact remains that distilled water may be at an advantage because it does not contain minerals. If the drinking water you mix with contains minerals, over enough time it can lead to deposit build-up that could prevent proper heat transfer. Speedway Motors offers a premium ready-to-use 50/50 antifreeze and de-ionized water blend from Afco, under part number 106100001.

Coolant additives can also help improve cooling by lubricating and eliminating the possibility of bubbles or foaming. Additives like Red Line’s WaterWetter, part number 91015709, have been Dyno tested to substantially improve heat transfer and reduce the possibility of corrosion. We also offer great options from both Pro-Blend and Afco.

To learn more about the importance of a fan/shroud with cooling performance and the difference between downflow and crossflow radiators, check out these other articles: Radiator Cooling Performance and The Difference Between Down-flow and Cross-flow Radiators.