Oil Change Trick

[EmeraldCoastSailor]

Not sure this is a good one or not but today as I was nearing the end of oil extraction via the dipstick tube, I poured about a fifth of a quart of fresh 15W-40 into the oil fill and continued sucking oil out. I completed extraction and refilled the oil and was amazed how clean it looked on the dipstick; I could barely see it. After I ran the engine to make sure everything was tight, I rechecked and there was just a little dark on the dipstick but not much; probably clearer than the first oil change 10 years ago. I always thought one had to live with the dirty look of fresh oil just because you can't get 100% of the oil out but using a small amount of oil to help with the final sucking stages of an oil change made a huge difference. Maybe everyone knows this trick and I just learned it? And I realize it probably doesn't make much difference in terms of engine protection.

[boom23]

I'll try it on my next oil change! It cannot hurt.

Thanks for sharing!

[Stu Jackson]

WADR, who cares? Really.

While a small amount may clear it up for starters, when the engine is actually run under load, it gets black.

Right away.

BTDT.

Nice idea, but usefulness as a factor is very low.

Thanks for sharing though.

Reality check: We bought our boat with 888 engine hours in 1998, 3600 now, with an ALL motoring trip to Vancouver Island from SF thrown in (165 hours), never bothered with your idea, although it had occurred to me over the years. Didn't seem worth it, regardless of the amount of dino used.

[valhalla360]

Might make you feel good but no real difference in engine durability.

As someone else said, as soon as you start running it, it will quickly turn black.

[Vasco]

Why waste good clean oil?

[sailorboy1]

Heck I don't want to get all the oil out. If I did I couldn't see the level on the dip stick.

[CaptTom]

Originally Posted by valhalla360

Might make you feel good but no real difference in engine durability.

Here's another angle. My theory is that bad things settle out in the bottom of the pan, and the more of them I can evacuate the better.

My current engines drain from the bottom of the pan anyway, but if I was using an extractor down the dipstick, I'd definitely try this trick.

[EmeraldCoastSailor]

Only a few hours on the new oil but I am amazed at the clarity. Not dark at all. No kill-joys needed as I realize that I am not materially improving oil performance. But I will "waste" a fifth of a quart at each oil change in the future to get sparkling clean looking oil just for the fun of it. It is the little things I suppose!

[LakeSuperior]

Find oil changing stuff, get in, pump out old oil, change filters (clean mess), add new oil, start engines, top off, dump old oil and empty jugs, and done. I am doing 4 engines, don't need extra steps to feel good about my self. I like doing other things better.

From an engineering point of view you are working on the 4th decimal point when you have 1st decimal point issues.

[hellosailor]

Even the honorary Scotsman in me has to say, there's some attraction to this. If your engine takes 5.7 quarts of oil for a change, you need to open 6 quarts, which are likely to be six liters these days. So when you are done you've got one bottle with a bare 0.3 quarts of new oil still in it....and what, you have to keep that dinky bottle around until the next oil change time?

It doesn't seem all THAT horrible to use the extra fraction up, in order to ensure the last of the old oil and sludge are gone. And not have to keep the extra mainly empty bottle around. (I know, for many folks constantly topping up oil, there's always a partial bottle to be kept on hand anyway.)

[EmeraldCoastSailor]

By way of an update after dozens of hours and 5 months, my engine oil has a darkness to it but it is several shades lighter than oil checked after a minute of running after any previous oil change.

[Simi 60]

Originally Posted by Stu Jackson

WADR, who cares? Really.

While a small amount may clear it up for starters, when the engine is actually run under load, it gets black.

Right away.

Depends on the motor and level of filtration.

My little 20hp Kubota genset is instantly black.

My primary 855 Cummins is honey coloured at the 250 hour change point.

[redsky49]

He raises a good point. Why rain on his parade?

If a few ounces of clean oil into the sump helps pick up more sludge, dirt, and contaminants, what is the downside?

My genset oil gets dirty quickly (I suspect blow-by past the rings), so I will give this a try on this weekend's oil change.

And really, what can you do with a leftover 3-4 ounces of oil?

[Simi 60]

Originally Posted by Simi 60

Depends on the motor and level of filtration.

My little 20hp Kubota genset is instantly black.

My primary 855 Cummins is honey coloured at the 250 hour change point.

I am thinking next time I do the big motor, I'll keep some of that honey coloured 37 litres to one side.

When the little motor needs changing I'll drop it and refill with the used big engine oil, run and drop, rinse and repeat a few times until I am draining clean coloured oil.

Then new filter and new oil and see how long it takes to go black.

They both use the same oil and the small motor has an easy drain tap on the sump and a remote filter to make changes easy.

[Greg4cocokai]

Originally Posted by Simi 60

I am thinking next time I do the big motor, I'll keep some of that honey coloured 37 litres to one side.

When the little motor needs changing I'll drop it and refill with the used big engine oil, run and drop, rinse and repeat a few times until I am draining clean coloured oil.

Then new filter and new oil and see how long it takes to go black.

They both use the same oil and the small motor has an easy drain tap on the sump and a remote filter to make changes easy.

+1! We had the same thing happening!