I wanted to clean an engine out a little bit without flush. I have about 2 new litres left of the oil in a can the type that's present in the sump and 5 litres of a different brand.
The engine holds about 3.5 litres. Both oils are semi-synth and 10w40. I was considering one of the following:
1. Drain oil when hot. Refill with the two litres from the "left overs" can and then add just enough to get it up to the mark with the new. Run the engine for a few miles or next day then drop it all out. Refill with fresh and replace the filter at this time. To clarify, both oils are new, I'm not re-using old oil!
or
2. Same as (1) but replace the filter at this "intermediate flush" change, and replace it again when it has its "real" change a few miles later.
I was just thinking along these lines after a discussion a while back with a (mechanic) friend where he suggested just filling with cheap oil and new filter and draining again after 10 miles (replacing filter again) , I'm sort of up in the air about doing the filter twice although I do have half a dozen anyway.
Any particular thoughts ? , bear in mind I have the oil and filters already so its more a question of which method would you prefer ? , I was only considering leaving the filter as the "fresh but only 2 litres" and the "new brand" will be mixed together but only for a short time, although tis debatable how much difference that would make in real life.
