Can Engine Preheater Be Plugged in All the Time?

Preheating your engine can increase longevity — especially if you’re operating in temperatures below 32?. Metals expand and contract as temperature fluctuates, and each metal does this with varying rates of expansion and contraction. Steel and aluminum have drastically different expansion properties which can affect the clearances in critical parts of the engine. In colder environments, aluminum will contract approximately twice as much as steel. In hotter climates, aluminum will expand twice as much as steel. This is the most critical reason for engine preheating - engine component clearances.

Engine parts are designed to have certain clearance between each other when operating in standard temperatures and operating ranges. Yet, when it’s too cold, these components can get tight enough to cause damage to the engine — crankshaft bearings are one of those items. They are supported by an aluminum case, while the individual crankshaft is constructed of steel. In areas of low temperature, the aluminum case contracts to the point where the bearings are too tight and have a high chance of causing damage to the engine.

You may notice quite a few benefits if you’re able to keep your engine above 60?: reduced engine stress, cylinder wear, and more efficient run-up times. In an ideal world, you’d be able to heat the entire aircraft to minimize wear/tear in everything. Often times this isn’t plausible. That’s why many pilots use installed preheaters or portable preheaters.

Aircraft usually have electronic preheating systems built in. Basic preheaters are constructed using a small electric pad that is attached to the oil slump of the engine. Other preheaters use a variety of options to heat the different areas of an engine: this includes heated intake tube bolts, heated bands, case heaters, and heated valve cover bolts. The main element to take precautions against is condensation.

Condensation is the result of warm, moist air flowing over a cold surface. Since water is a key contributor to corrosion, preheating an aircraft with just an oil slump heater for extended periods of time can result in premature camshaft and cylinder wear. This can be avoided by investing in a complete engine heating system.

Portable engine heaters are a necessity if you don’t have a preinstalled version. These systems require electricity and propane to create a strong flow of hot air into the engine compartment. The air can be blown into the bottom cowl of the exhaust opening or through the front cowl at the air inlets. At a minimum, try and get the entire engine to be above 40? to prolong your engine’s long term-health.

At ASAP NSN Hub, owned and operated by ASAP Semiconductor, we can help you find all your preheating parts for the aerospace, civil aviation, and defense industries. For a quick and competitive quote, email us at or call us at +1-920-785-6790.


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