To flush or not to flush, that is the question

[Donkey]

Hi chaps,
Any views on whether to flush or not prior to an oil change?

Cheers,
Brian

[Lingen]

Brian.
If what came out wasn't filthy, it shouldn't be necessary. There is enough detergent in a good 20/50 oil to keep contaminants on the move, and get them in to the filter.
Mike.

[singapore stag]

When I put new oil into thhe rebuilt engine the oil that drained out was like new oil, I did not how long its been in there bit but had to change it for peace of mind.

[wilf]

If you have good oil pressure and no other concerns about the oiling system, I personally would not flush. Or, to be more precise, I would not use a flushing oil. If the old oil was particularly dirty, I might, however, put the fresh oil and filter in and change both again after a couple of hundred miles or so - as good as a flush as the fresh detergents in the new oil will do their work.

[Donkey]

Thanks guys.
Stay safe.

Kind regards,
Brian