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Stewart Components Tech Tips |
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Tech Tip #4 - Coolant, Fans, and Hoses
Coolant
UNEQUIVOCALLY WATER IS THE BEST COOLANT! We recommend
using a corrosion inhibitor comparable to Prestone Super Anti-Rust when using
pure water. If freezing is a concern, use the minimum amount of antifreeze
required for your climate. Stewart Components has extensively tested all of the
popular "magic" cooling system additives, and found that none work better than
water. In fact, some additives have been found to swell the water pumps seals
and contribute to pump failures.
In static cooling situations, such as quenching metal during heat treating,
softening agents (sometimes referred to as water wetting agents) will allow the
water to cool the quenched part more evenly and quickly. The part will cool
quicker, and the water will heat up faster. However, an automotive cooling
system is not static. In fact, the velocities inside a cooling system are
comparable to a fire hose forcing coolant against the walls of the engine's
water jackets. If the softening agents actually aided in cooling the engine, the
temperature of the coolant as it exited the engine would have to be higher
because it would have absorbed more heat.
Fans
Electric fans have improved
tremendously in recent years, in both quality and reliability. Electric fans now
outperform mechanical fans in nearly every application, except towing and dirt
oval track racing.
When using a mechanical fan, a properly designed
shroud must be used. Most mechanical fans are not designed for high RPM use:
they can have serious vibrations problems, due to air turbulence, when run over
6,500 RPM. This is a turbulence problem, not a balance problem, and will destroy
the water pump and components in front of it. The large fans preferred by dirt
oval track racers can consume up to 18 horsepower at 6,500 RPM.
Do NOT run a mechanical fan that is any larger than
required for the application.
Flex fans are a poor design for performance applications. They move less
air at higher RPM, and only consume a fraction less power than standard fixed
pitch fans.
Clutch-style fans are inconsistent and we do not recommend their use for
any application, if possible.
Hoses
Standard full-size hoses should be used to ensure maximum
flow. Smaller "AN style" hoses decrease flow and hence inhibit proper cooling.
Next Tech Tip - Radiators & External Plumbing |
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©2004 Stewart Components. All rights reserved. |
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