Like many of you, my S uses oil like gasoline, about 1000 miles per quart like clockwork. Over the life of one 7500 mile oil change I'm spending $70-80 on makeup quarts of oil at $10ish per quart.

I'd like to buy 5QT ($23) jugs and just top up from that to save a little money and frequent trips to the autoparts store. Is there any risk of contamination/condensation from keeping a re-sealed 5QT jug around for the 6-8 months it takes me use it? I assume not, as the oil already lasts 6 months to a year in a very rough environment (inside the engine).

 

You're ok. My guess is the life of an open, but sealed oil bottle is years. Many years.

 

I agree. Less than a year is not a problem.
I just picked up a 5 quart jug of Pennzoil synthetic for $15 after a rebate last week.

 

Keep it capped, definitely safe for years.

 

If you have a small business or shell corporation open a commercial account, I get oil a bit cheaper because of it.

 

Oil bottles leak like hell, good thing I had it double bagged. I now keep the 5qt bottle in the garage, and picked up this camp stove fuel canister to keep a quart with me

 

You can use a rubber glove as a gasket for the cap on an oil bottle.

 

If you don't mind, what oil are you using?

ROD

 

Or a condom?

 

Castrol Edge (formerly Syntec) 10W-30