Why it might be important to clean out the oil pan and pickup with a head gasket replacement,

Somebody should develop a valve that would replace drain plug and could be controlled with bluetooth. I could just hit ”drain” in app and out the oil would come

 

What about the filter? You still have to get under the car to change the filter.
I drive the right front wheel onto a lift, or jack it up, depening...
So now it's at an angle to head toward the drain.

The very little oil left behind is nothing. You will never get it all out unless you take the engine apart.
4 ounces of 145?

I wished ALL engine had the oil filter at the top like BMW. SUPER easy to change.
And with this system, you'd never have to get under the car for an oil change.
Unless you drop something.

 

LOL! Reminds of the person who said we don't need actually need weather stations and monitoring equipment anymore; when asked why, they said because we have the iPhone/Android weather App, and it tells you all you need to know.

 

Yeah I'm with you on whether this is worth it or not, but if you drain the car level, as probably all shops and quick-lube joints do, I think there could be up to 14-16oz of oil left below the drain plug hole. With the abundance of "oil-burn" issues that these Toyota engines have, it would seem wise to get all the old crap out of there that you could easily reach. And if you subscribe to the not-changing-filter every other oil change, you could save quite a bit of time by doing the pella-method every other time. But I think pulling the oil filter each time is wise because you do get a pretty good amount of oil out that way - however - I don't think its more than the amount remaining in the bottom of the pan on a level change.

And I really appreciate my old vw golf top-down approach to oil changes. not sure why all cars are not done this way. Just think of the shop savings in time on lifts, etc. also, with a vacuum drain method, it would be much easier to direct oil exactly where it needs to go, container-wise. you could design a central vac system in your shop with a little vacuum dipstick tube and just pull oil directly to its final recycle bin. the up-front engineering would be a bit more, but probably worth it over the years.

 

The amont of the oil left during a drain, is not important.
At the extreme most, 1%.

What about changing the oil filter?

There is no point in changing the oil if you aren't ging to change the oil filter.

 

Volvo had the same in their diesels. Absolute dream location and clean job to replace. Honda is total opposite. Hard to reach and messy operation Probably worst i’ve seen

 

Couple weeks ago i did Honda oil change. Even punched a hole to filter and tried to drain it before opening. No luck. It was as messy as usual. CV axel, control arm etc got their annual oil shower

 

What Honda? Who put the filter on? I never had a lot of issues, but maybe a recent model?

 

Not really.
According to Toyota, 12% of the old oil is left with filter change, and 18% is left without filter change.

 

??? Never heard that before.
Hundreds of millions of cars have done oil changes and some oil always gets
left in the engine. This is normal.

 

Just did a second Prius OC a few days ago. Same procedure: jacked the front up 6", drained most oil from the pan plug and removed the filter. Had the Pella sitting next to me outside of the box, so gave it another try on my other Prius. worked easily and great. the nice thing was I didn't have to wait for the drip, drip, drip to end. So, I could immediately clean and re-install the plug with a new washer and get on to the filter replacement. I wish the oil filter housing, which is higher than the oil pan, drained via gravity into the pan in some way, but it looks like it doesn't. if it did, I would seriously consider just pulling the old oil out with the Pella - less mess and oil showering into the oil catch basin, quicker re-assembly, pulling slightly more oil out of the pan. If oil is hot, less chance of getting burned. Not messing with the oil drain plug means less chance for stripping out that dam thing. On the off chance that trace amounts of heavier-than-oil water or metal debris is in the bottom of the pan, I know I'm sucking that crap out of there. Less time screwing around on my back under the car.

Actually, the more I ponder it, I'll probably just pull all the pan oil with the Pella next time and pop the filter off the old-fashion way. Will still be safer, save time, be less messy. The only downside right now is the new oil is so clean because I'm pulling probably most oil out, that I cannot easily see where on the dipstick the fill level is at! With the old way, some of the old oil would mix and darken the new oil pretty much right away.

 

based on my measurements, on a level oil change draining from the plug (what all shops with lifts do), I think you could have upwards of 8-10% of the old oil in the bottom of the pan. not that much, but not trivial either. And if in the off chance, there is accumulated water, that will sink to the portion of the pan. I know that seems unlikely, but my oil catch can sure fills up with condensed water in the winter.

 

Any moisture is from the engine heating and cooling in the occ.
8-10% is not realistic. Even if it is, it is not worth worrying about. It is nothing.
It is normal.
If you are so worried about it, after changing the oil and filter, heat the engine to normal operating
levels, drain the oil, change the filter and do it again. Maybe even again do it a 3rd time.

 

The 12% that Toyota says remains includes all locations---in the pan, in lines, trapped in the head, in the pump, and wherever. It's not a problem. Suction method may or may not empty the pan more thoroughly than the drain plug does. That depends on whether the end of the suction hose lands at a point lower than the bottom of the drain opening.
Water condensed by your catch can system in winter is not representative of what's in the sump.

 

with the Prius pan, it was designed (correctly or not) to _not_ drain all the oil. the notch in the Honda pan is much smarter design than the Prius. I'm really not sure why the Toyota engineers did this! OCI Update: I have been pulling oil from the dipstick tube now for 4-6 oil changes on various Prius, and it works good. it doesn't pull much extra oil (maybe 6 ounces) but its super easy, and the tube never gets stuck or has a problem going through the dipstick guide. i can also hear the pella hose bottoming out on the pan itself, so its making it down there to some level below the normal drain hole line.