"Ben Jackson" wrote in message
news:CQkJb.261117$_M.1211945@attbi_s54...
Let's say you're at a point where you need to add a quart of oil.
You've decided you would like to finish this oil change interval at
a lighter weight (eg you put in AeroShell W100, SAE-50, and now it's
freaking cold). Can you add a quart of a (substantially?) lighter
weight oil (presumably in the same 'series')?

--
Ben Jackson

http://www.ben.com/

Absolutely. All aviation oils are compatible, and have to be to meet the
appropriate spec's. Otherwise, you'd be SOL if you needed to add a quart of
oil and the FBO on the airport you stopped at didn't carry *your*
brand/weight of oil.

KB