From Dave Hsu (hsu@eng.us.uu.net): Since there seems to be some recent interest in "oil suckers" and conflicting information about their compatibility with the newer Mercedes 112- (ML320) and 113- (ML430) series motors, here's a summary of my recent experience. My intention is to do my own oil and filter changes between FSS-indicated service intervals. First, the backgrounder. The idea is that you warm the oil a little to help it flow, then snake a suction line down your dipstick tube to draw the oil out of the bottom of the oil pan. You can find a variety of oil change pumps at any marine supply store; since you can't just jack a boat up and pop an oil drain bolt, motorboaters rely on these things. Small oil change pumps are generally of two varieties: inline transfer pumps, and vacuum cans. Inline units may be cranked, motor-driven or air-operated (using a venturi) and generally have both an inlet (suction) and outlet connection. A separate open container is used to collect the fluid. Vacuum cans are sealed systems consisting of a container, a suction probe, and a pump used to depressurize the container. The system must hold vacuum in order to work; this also means that you're limited to the capacity of the can. Many of these are designed to stop sucking when the can reaches capacity. The Topsider MVP is a vacuum can unit resembling a round gasoline can with a 2+ gallon capacity. Capacity was an important selection factor; the pump sold by Griot's Garage is the other commonly found design but only holds 6 liters, inadequate for the Mercedes 8 liter (8.5 qt) sump. There is some debate as to the Topsider's actual capacity, but I was able to empty my sump completely into it without overfilling. The suction line is in two pieces; there's a 4-foot piece of clear vinyl tubing that attaches to the tank, and at the other line it's connected to a narrower 4-foot piece of polyethylene tubing that acts as a flexible suction probe. I read a recent claim in news:alt.auto.mercedes that the 112-series engine could not be used with the Topsider due to the double-bent path of the dipstick tube. This is bunk. I examined the tube from above and below to verify that an inserted line would reach the low part of the sump near the drain bolt. While it does take two bends to clear the cylinder head and alternator, the dipstick tube has a perfect vertical shot into the sump on the same side as the drain bolt; there's even a little overengineered pedestal cast into the engine block where it enters. It was easy to use. Starting with a cold engine, I warmed it up until the coolant temp gauge read about 50 deg C. Shutting down the engine, I removed the plastic engine cover, dipstick, and oil-fill cap. I also unscrewed the oil filter cap all the way to release the anti-drainback valve. Following the Topsider instructions, I closed its pinch clamp and developed about 50 strokes of vacuum in the can. I set the can on the ground in front of the ML and fed the suction probe down the dipstick tube until it bottomed. This time I took an extra step of withdrawing the suction probe and comparing the amount that fed in to the height of the engine to make sure I wasn't just hitting an obstruction, and marked the probe where it met the top of the dipstick tube so I'll know next time. It's exactly 25 inches from the bottom of the sump to the top of the dipstick tube. Releasing the clamp started the oil flowing. It wasn't especially hot or thin, so next time I think I'll warm it until the temp gauge reads 60. Periodically, I gave the pump a couple extra pulls to help the flow along. There was a prominent slurping sound when it was finished. Don't forget to retighten the oil filter cap to 25 N-m (18 lb-ft). And I shouldn't have to tell you to recycle your used oil. Based on the amount of Mobil 1 needed to refill the engine, the pump got all 8 liters of old oil out. Except for checking the path to the sump, I didn't have to touch the ground. Least messy oil change I've ever done. You can mail-order the Topsider (about $40, but I see there's currently a 10%-off web sale if you type "INT10" under special instructions) from: https://www.boatus.com/cgi-bin/SoftCart.exe/boatusnow/products/162027.html?L+boatusnow+purx8730+911790443 I picked mine up from the local retail location since sales tax was cheaper than shipping.