I was dump and accidentally put gasoline in my diesel engine car and happened to have just received this in the mail so I could do oil changes without climbing under the car. Well, it worked like a champ helping to suck out approx 13 gallons of gas/diesel mix. Yes it was slow, but the hose is very small and the suction is from hand pumping so it works as fast as it can. I even used the lines on the bottle to estimate how much I removed.--When I used it later to change my oil, it worked great there too. Don't over pump, but I did have to pump more frequently after a few minutes to keep the flow. And I made sure the oil was warm before do this so it could flow easier. I've only used it once so far, but I think it will keep going. Easy instructions too.