Protecting your engine during the COVID-19 lockdown

Lycoming engine

With lots of us sheltering in place and some airports locked down, there’s not as much GA flying going on as usual. This puts our piston aircraft engines at risk for corrosion damage, and that can get very expensive. Engines don’t like to sit unused. 

If your engine is inactive and likely to continue that way for awhile, it’s important that you take steps to mitigate the corrosion risk. There are a couple of ways to do this.

Pickle the engine…

The best way to protect an engine from corrosion is to “pickle it” (or more formally, to place it in “flyable storage”). Continental Service Information Letter SIL99-1 and Lycoming Service Letter L180B cover the procedure. Both call for these three things to be done:

Tanis pickle kit
Tanis “pickle kit”
  • Drain engine oil and service the engine with preservative oil such as Aeroshell Fluid 2F or Phillips Anti-Rust Oil. The engine should then be run to ensure that the cam, lifters and cylinder walls are thoroughly coated with the preservative oil.
  • Remove the top spark plugs and replace them with “dehydrator plugs” that contain desiccant crystals.
  • Place cloth bags of desiccant crystals into the induction air intake and exhaust pipe(s) and then seal them up (e.g., with duct tape).

That’s all there is to it, and all of these actions are “preventive maintenance” that an aircraft owner is permitted to do on his or her own without requiring an A&P mechanic to be involved. Of course, if you prefer to have your mechanic do it, that’s fine.

Tanis Aircraft makes a “pickle kit” that includes everything you need to do this. It’s available from Aircraft Spruce. They sell a 4-cylinder kit for $180 and a 6-cylinder kit for $270.

…Or use an engine dehydrator

Black Max engine dehydrator
Black Max engine dehydrator

An alternative to pickling is to use an electric engine dehydrator. This requires that you have access to 120-volt electrical power, and works best if the aircraft is hangared. A dehydrator is a small electrical air pump designed to fill the engine with dehydrated air and to force any moisture out of it. The dehydrator is connected to the engine through a tube that can be attached to the oil filler port or breather tube (whichever is more convenient).

There are two types of dehydrators. One type has a chamber containing desiccant crystals to dehumidify the air before it goes into the engine. The other type (which is more expensive) dehydrates the air by refrigerating it, much like an electric room dehumidifier. 

Aircraft Spruce sells a desiccant crystal dehydrator (“Engine Saver”) for $325. Aircraft Components Inc. sells its refrigerating-type unit (“Black Max”) for $595.