Questions on using an Oil Pump to change oil

[Dave S3948]

I have an Oil Boy pump that I used with marginal results. <br /><br />First of all my engine is a 5.0 Mercruiser. I have the boat in the water so I thoroughly warmed up the engine so the oil would be hot. After that, I punctured the top of the oil filter to allow it to drain into the pan as much as possible. This also makes less of a mess when you remove the filter (which is what I did next).<br /><br />The Oil Boy pump has the "Garden Hose" adapter which screws on the top of the Mercruiser dipstick so I used that. After several pumps to start the flow everything went fine. I waited until the pump started sucking air before I stopped. <br /><br />Here is the problem........I was only able to extract a little less 3 and 1/2 quarts. I remember a lengthy post on another forum debating the capacity of the 5.0 and when Mercruiser was finally brought into the act they admitted that this engine only held 4 and 1/2 quarts with the filter rather than the 5 stated in the owners manual. But that still leaves me short a bit over one quart.<br /><br />So this brings to mind several questions. If you change your oil using a pump, how many quarts do you typically extract? Does anyone know how far into the pan the dipstick tube extends? If it doesn't go all the way to the bottom of the pan then I would guess that is part of the problem.<br /><br />I am just looking for a satisfactory solution and would welcome any suggestions you folks may have.

 

[Alumarine]

Re: Questions on using an Oil Pump to change oil

The dipstick tube does not go to the bottom of the pan. I don't know about your pump but the one's I've used have a hose that goes down the dipstick tube and I can feel it when they hit the bottom of the pan.<br />Even though you put a hole in the oil filter there will still be quite a bit of oil in the filter media. Your used filter is probably quite a bit heavier than a new one.

 

[MRS]

Re: Questions on using an Oil Pump to change oil

I know this will sound silly but did you check your oil level before you started pumping the old oil out?

 

[craze1cars]

Re: Questions on using an Oil Pump to change oil

I'm no boat mechanic, but I'll share my personal experience. Mine is a 3.0L, and last time I changed mine with a hand pump, I did get nearly a full 5 quarts out. I did not mess with the "garden hose" adapter, and instead just stuck the long skinny tube all the way down into the dipsick tube until it bottomed out. I could actually hear the tube clanging into the bottom of the oil pan when I did this. It was rather slow to empty because the tube is very skinny and just doesn't move oil very fast. But after 10 minutes of pumping I feel I got it all out except for probably a shallow puddle.<br /><br />I'd suspect maybe your oil dipstick tube is not all the way down to the bottom of the pan so it's sucking air when there's still another inch or so of oil laying there. So you might want to use the long tube and just shove it all the way in there and try to get more out.

 

[Dave S3948]

Re: Questions on using an Oil Pump to change oil

MRS.....I checked the oil level before I pumped and it was OK.<br /><br />craze1cars........I tried using the skinny tube but was not able to get it all the way thru the dipstick tube for whatever reason.<br /><br />Since Mercruiser is the one that puts the "garden hose" conector on the dipstick, I am still somwhat baffled why you wouldn't use this for an oil change. Likwise, I have seen our dealers Mechanics connect to the dipstick tube exactly as I did.

 

[rodbolt]

Re: Questions on using an Oil Pump to change oil

that tube goes to the bottom of the pan or it did when it left the factory. if your hull was in the water and not level some of the oil may be in another part of the sump. dont punch the filter makes to big a mess. use a 1 gallon ziplock and just let it drop in the bag and zip it.<br /> ya could have had an airleak or someting but I change a lot of oil and never had a problem. current changer is called a slurper, draws a vacum down on a 12 gallon air tank. I can suck an 8.1 volvo or a pair of yam f225's on a charge and it uses standard air pressure to recharge. you could charge it here and take it to san francisco and suck a sump . I can also leave in on the dock or on the ground and drain the oil.

 

[Richard Petersen]

Re: Questions on using an Oil Pump to change oil

Getting most of the oil out is all that is necessary. Changing the oil filter takes out ALL the bad and dangerous stuff that travels in the engine. Perfection is a waste of time. The small amount that is still there is overpowered by the new oil and its full supply of protective additives. Just change it. Not a surgical operation.--------------------MAKE sure the plastic tube in the dipstick is STRAIGHT. It does a better job.

 

[Scaaty]

Re: Questions on using an Oil Pump to change oil

And don't add more than what ya took out, plus some for filter (I always pre-fill the filter myself).......then check the level. Then start it up, and check again.<br /> And the punching a hole in the filter is a waste. Loosen the filter, then cover it with a good grocery bag or ziplock. All this pertains to a vertical mount filter of course. And you will be surprised how long it takes to fill a filter...takes time to go through that media without pressure!

 

[Manipulator]

Re: Questions on using an Oil Pump to change oil

I have a "Tempo" oil pump and it works great. I thought as others did that the dipstick did not go to the bottom of the pan. I followed the dipstick tube down and it attaches to the bottom of the oil pan and does suck it all out. I have a threaded dipstick tube (guess this is what others discribe as the garden hose attachment) and suck it all out through the dipstick hole. A pint is usually left in the system due to the oil that remains in the oil hoses that goes to the remote oil filter. <br /><br />I ran into the same problem thinking a quart or so was left behind. That was because many times I had the trim down all the way (I have an OMC and the whole engine elevates up or down) so this would bring the engine up thus making the reading appear to have an extra quart. Now I trim the engine to where it is level and then check it.

 

[lakelivin]

Re: Questions on using an Oil Pump to change oil

If the first thing you did was puncture the oil filter, doesn't that create the opportunity for air infiltration that will reduce the efficiency of your pump?