As an addition to TOMFEN's innovative use of the garden sprayer, which I intend to adopt forthwith, here's a couple added wrinkles others might want to try.
I'm sure it is common knowledge for many DIY oil changers, especially if you have ever tried an outdoor oil change in the winter: immerse the plastic oil bottles in a bucket of hot water for a few minutes to reduce the oil's viscosity. This will speed up it's passage through filter screens and tubes connected to funnels, like the one I have been using, and the cap and tube atodalen uses, and I imagine will really help shoot the oil through the garden sprayer hose more easily, as well as the tubes some owners use with powered transfer pumps.
However, I'm going to skip the water bath and spray-paint my soon-to-be-modified TOMFEN garden sprayer tank flat black. Then I can pour the correct quantity of oil into the tank, close it up and let it sit in the direct sunshine for a while. No water or fuel to heat it needed.
The other mod I'm going to make to TOMFEN's idea is to use a small plastic spring-clamp, (got 'em cheap at HF) or even a big plastic clothes pin, in place of a twist tie to keep the sprayers valve handle open. I already use this technique on my power washer wand to give my poor arthritic knuckles a break on long cleaning jobs since it's valve lock does not work. Easy on, easy off with one hand and a lot quicker than a twist tie.
5 yrs US Army, 35 yrs US Customs (retired)
RVing with DW, kids, grand-kids, and multiple Golden Retrievers since '77
'99 Southwind 36Z Ford F53 - '08 Saturn VUE XR AWD Dinghy