View Full Version : Stupid question How does one replace the oil in a V8

04-07-2006, 10:43 AM
"Hello everyone,
this may be a stupid question, but how do I get the oil out of a 5,7l Mercruiser V8?

I can't get a drop out of the engine, do you have any ideas why and what I should do? I have tried using a pump with a thin hose down where the oil stick goes. Nothing. The engine was warm and the pump works. I know because I have used it before and I can pump out the water from under the engine with it. And yes, there is oil in the engine - at least the oil stick indicates so. I would prefer not to remove the oil filter creating a mess in the boat.

I would be very grateful for explanations/help!"

04-07-2006, 11:52 AM
"Instead of sticking a very small hose down the dipstick tube, just connect the rubber adapter part of the pump suction over the dip stick tube (with the dipstick removed). The dipstick tube goes all the way to the bottom of the oil pan, within a 1/4" or so anyway. If you change the oil routinely, and don't have any other problems like water in the oil, the little bit of oil remaining when the pump looses suction is insignificant."

04-07-2006, 12:00 PM
"Thanks Troy,
I will have to try that! I am not sure whether I have a rubber adapter but will try to get one right away."

04-09-2006, 06:40 AM
"The idea is to remove any restriction in the line, so a large hose must be used from the pump to the dipstick tube.


PS: I took me several tries and a few pumps to get the oil of mine at one time. I now use an old propane tank as a vacuum receiver, with the other engine (twins) as my vacuum pump. (You can also use a car or truck parked nearby.) The vacuum sucks out the oil really nice, and it ends up in the tank--not all over the bilge."

04-10-2006, 08:12 AM
"Thanks for your replies and suggestions, my question was stupid, I must admit. But I finally managed to get the oil out! I didn't find an adapter or a larger hose to put around the dipstick tube, but using a thinner but longer hose I managed to pump out the oil. The first hose must not have reached all the way down after all (I was fooled by it getting oily when inserting it into the dip stick tube). With the very cold weather and the thin hose it took me an hour to remove the oil, but now it's out!"