How long for an "oil flush"?

[KCJeep]

I had a recent used oil analysis that I thought should have been better. Long story short I've been using oil blends and additives and I refilled with a similar mix before I got my used oil analysis results. But those are other topics and we have other forums for that as well, not the purpose of my post here.

But now I want to try some runs of straight oil to compare. Since I have another similar brew in now, I want to drain it, do an "oil flush" run of Pennzoil Conventional, then refill again with Pennzoil Conventional and do a full OCI and used oil analysis again to see if there's any improvement.

My question, how long for the straight "oil flush"? I was thinking 1 to 1.5k but I really don't know. How long you think it would take to get the new "flush" oil to essentially strip and pick up what is in there now? I want to get an accurate used oil analysis on the follow up run of Pennzoil Conventional.

Cost isn't an issue I've got plenty of bargain Pennzoil Conventional sitting around the flush run will only cost me about $8.50 including filter.

Thanks!

 

[05LGTLtd]

If your just diluting residual mix, it could be a drive around the block until warm interval. Anything from 500 to 3k will act as a purge.

 

[KrisZ]

Nobody will be able to give you an accurate answer. Since there is always some oil left after OC, there will be some left over additives lingering in the system. It may take several OCIs to truly flush them out or use them up.

 

[TFB1]

If you need to add run it till it's close to a qt low and then change it...