One conclusion seems to be that suction/evacuation devices using a probe are more efficient than those using a hose attached to the top of the dipstick tube (as mine does). And that draining through the pan is more efficient than either. Being somewhat of a purist, I like to pour a half-quart of clean oil through just before sealing things up for the refill. It makes me wonder just how close to the bottom of the pan the dipstick tube actually is. On my C280, the refill only took seven (7) quarts. Many here know the actual capacity is 8.5 quarts. This after suctioning the oil several times over the course of several hours just to make sure it had time to drain down. And yes Larry, it was "hot" when I started!
Another conclusion we might draw is that the shops (or manufacturers - hint, hint
) that tout oil evacuation may not be getting out as much oil as we are wont to believe! Hmmm???
For those who are curious, I used an air vacuum pump as the centerpiece of the operation. A stream of high-speed air is passed over a perpendicular opening and creates the vacuum in that opening. I understand this is a primitive and small-scale version of what some of the pro shops use. I wanted something relatively simple and "elegant." No extra motors, wires, hand pumping, etc. I studied the Mighty Vac
(my personal retail favorite) and others and decided to try my hand at building my own. Incidently, as I dicovered after making mine, Mighty Vac makes a version that also uses the compressor/venturi principle (click here
). The prices at the Tool Warehouse in the links are the lowest I've seen. Total cost to build mine was around $25-30, not including the compressor, of course.
I got the (air pump
) at Harbor Freight Tools. It's occasionally on sale for under $10. The translucent 3.5 gal. bucket was from Lowe's for about $3. You can get the lid there or from Home Depot. The reinforced hot tub hose (5/8" OD, 3/8" ID) was from Home Depot at .44/ft and provides a perfect friction fit inside the top flange of the dipstick tube (for some reason it was .99/ft. at Lowe's). I got the 3/8" brass "barb" hose fittings but you could probably use plastic ones which are much cheaper. They're a pretty good fit, so I didn't even use clamps. I also used a couple of big 5/8" washers on the lid for the hose fittings.
I'm wondering about using ramps when draining the oil. Since the vehicle is not level are you going to be able to get as much oil out through the plug? Doesn't the car need to be level to get the most oil out?
Well, crap. There goes my lunch break! Anyway, thank you all for your comments and compliments and even the toungue-in-cheek pokes! This really has been a fun project and topic for discussion.