On 22 Dec 2006 05:09:53 -0800, "cpw" wrote:

I live in northern lower Michigan where we have real winters some years
(not this one yet). My partner and I own a 2000 Cessna 182. We are
currently debating the proper use of the Tanis engine heater. It has
been our practice in the past to plug the heater in after a flight and
leave it plugged in until the next. We have heard lately that best
practice is to only use the heater for a few hours prior to flight.
Any opinions among other owners in cold climes?
Thanks. CPW

My a/c is based in NH and Maine, and I've had a Tanis Heater (oil screen
and heated intake bolts) for 10 or 15 years, along with an engine cover.

When OAT's drop below freezing, the heater gets plugged in and the cover
applied. It stays this way constantly throughout the winter (obviously not
when I'm flying, which may vary from a few times a week, to a few weeks
between times.

No signs that this procedure has lead to corrosion (and I do get oil
analyses with oil changes).

Usually, the CHT's read about 100°F, and the oil about 80°F.
--ron