If you're using penetrating oil to loosen a stuck nut or bolt, you may be wondering how long you should let the oil sit before trying to remove the fastener. The answer depends on a few factors, but in general, you'll want to let the oil penetrate for at least 15 minutes before attempting to remove the stuck part.
There are a few things that will affect how long it takes for the oil to penetrate and loosen the stuck fastener. The type of penetrating oil you're using can make a difference - some oils are designed to penetrate quickly, while others may take longer to work. The size of the fastener also matters - a smaller nut or bolt will likely come loose quicker than a larger one. And finally, if the fastener is particularly stubborn, it may take longer for the oil to do its job.
If you're not sure how long to let the penetrating oil sit, err on the side of caution and give it more time rather than less. It's better to wait an extra 10 minutes for the oil to work its magic than try too early and end up stripping the threads or breaking something else.