Ownership: Cold storage

Keeping your engine happy during winter weather

February 1, 2013

winter aircraft maintenance

Dave Belfi joined that species of travelers known as snowbirds in 2011—that is, he decided to spend part of the year in Florida while keeping a primary residence in Michigan. Belfi regretfully decided he couldn’t afford to bring along his 1974 Piper Cherokee to the warmer climate.

Since the airplane would be sitting for at least two months, he didn’t simply throw a blanket over the cowling and lock the hangar door.

“I changed the oil,” he said. “I did add ASL CamGuard [an oil additive]; this is the first time I’ve used it.” Belfi says he prefers nonsynthetic oils for storage, so he used Phillips XC 20W50. He pulled the spark plugs and sprayed fogging oil on the cylinders through the spark plug holes; rotated the prop several times to spread the oil; then replaced the plugs. He also plugged the exhaust pipe and the air inlet. His last step was to make sure the fuel tanks were topped off.

Belfi’s steps will preserve his Cherokee’s engine during the extended period of time on the ground.

What about those of us who plan to fly on during the cold weather? As you learned in ground school, normally aspirated engines perform well in cold temperatures—but they don’t like cold starts. The rapid change in temperature is tough on the cylinder heads. Cold, thick oil takes longer to pressurize and provide lubrication, which places those parts protected by oil at risk. So one of your first concerns is to warm the oil whenever the mercury drops below 20 degrees Fahrenheit (or according to the engine manufacturer’s recommendation).

Short of a heated hangar, how do you do that? If your airplane is kept outside and there’s no source of electricity, you could ask to have it moved to a heated hangar or call for a preheat from the FBO. Failing that, some owners have hooked up portable propane heaters—such as a Red Dragon—to a car battery, then blasted nice, warm air into the cowling through some ducting.

A hangar with electrical power gives you more options. A preheat system such as those manufactured by Reiff Preheat Systems or Tanis Aircraft Products can be plugged in and left on for several hours, thus ensuring you won’t find a cold-soaked engine when you arrive at the airport (see “Heating Resources,” previous page). These systems have elements that need to be installed on the engine’s cylinders or oil sump. Once installed, however, they’re ready for use wherever your airplane happens to be, as long as you have a source of power. Some can be operated by timers or even smartphone apps (see “Briefing: Products,” page 32).

You could, of course, go the light-bulb route: Cover the engine with a blanket and install cowl plugs. Hang a 150-watt light bulb inside the cowling, but well away from oil drips, fuel, or other possible sources of combustion. Many owners swear by this. I confess I’m a little leery of it, but I suspect it’s because of that year when the Christmas tree fell over and one of the 1960s-era decorative light bulbs burned a hole in the carpet.

Email jill.tallman@aopa.org.

Heating Resources

A sampling of products to warm your engine on cold days: