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03 E320 4M Wagon & 97 E320
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Discussion Starter · #1 · (Edited)
Many of us use some kind of vacuum device (oil suckers) to change oil in our cars. I have used several kinds: small 12-V pump, Liquivac, large 12-V pump on bucket, and lately the Mityvac (8.8 L model). However, I was never satisfied with the speed of any of these oil suckers. The main reason is the small tube that inserts in the dipstick tube. Even with hot oil, it is very slow to vacuum out 7 liters of oil.

I know that dealers use air powered device that uses the Bernoulli’s effect to vacuum out the oil by using the dipstick tube itself as the sucking tube. Due to the much larger diameter of the dipstick tube, the speed is very fast.

Kajtek1 has been mentioning several times that his Mityvac came with a large tube that can be attacked to the outside of the dipstick tube directly so he can vacuum out the oil pretty quickly. Mine, however, did not come with such a tube, just three small tubes that can be attached to the Mityvac.

I determined to try Kajtek1’s method this time so I went out and got 4-feet of 5/8 diameter EPDM hose. There is a Tractor Supply Co (Farm-Fleet) in my town and they stock these heavy duty hoses for agriculture applications. It is a very heavy duty hose and its size fits perfectly on the Mityvac and a little tight on the dipstick tube so I used a screwdriver handle (overnight) to enlarge it a bit. A hand clamp is used on the dipstick tube end to keep it tight. You can use other hoses but this one I used won't collapse and the wall is very thick. Plus it is EPDM so it has lots of elasticity to seal the dipstick tube.

The result, it is a day and night difference. I had to keep pumping on the Mityvac in order to keep oil flowing (it goes that fast). I did not use a stop watch to time it because I was just testing the idea but it was very quick to vacuum out the 7 liters of oil. I did take out the oil filter (some oil there, obviously) and open the oil filler cap while vacuuming. Thanks, Kajtek1.

After I finished, I took a few pictures. If you change oil from the top, you should give this a try.
 

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Neat idea.

Of course you mean "dipstick tube" when you write "dipstick" (which you've removed).

The dealer tool I've seen goes into the top of the dipstick tube and seals via o-rings.

I'd note that I have the shop air powered MityVac and if I get the plastic tube stuck to the bottom of the pan it tries to collapse the MityVac once the oil's out. Since you're hand pumping, you're proabably not as likely to walk away during the process, but your approach maybe could be even more likely to collapes the MityVac without close monitoring and it clearly is a good idea to be sure the oil fill cap is removed. (I'll cut my tube at an angle for next time.)

I'm less likely to try your approach in addition because I use the MityVac on my VW TDI, too, and it has a plastic (and fragile) dipstick tube.
 

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Discussion Starter · #3 · (Edited)
Thanks, Kent.

I will go back to edit the dipstick tube.

It is so fast and I will be doing the 97 E320 tomorrow.

About the possibility of collapse of the Mityvac. I think the way I used will be less likely. I think the reason is that there will be no obstruction in the system so any vacuum created in the Mityvac translates to oil being sucked in. In another word, the vacuum will be low in this large tube case (and that is probably why I had to keep pumping but the flow was fast). With the small tube (if it is blocked), then a higher vacuum will be created in the Mityvac, causing it to collapse.

I have not experienced Mityvac (hard plastic) collapsing but have seen my Liquivac collapsing once (soft plastic).
 

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I don't know if it would or wouldn't work, but there is no avoiding getting under the car and removing the pan to change the transmission filter.
I know, but I don't plan to change the trans filter every time I change the ATF. Hehe..
 

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I used this method to change (half of the) transmission fluid in a POS escort. That car is essentially dead now, but not because of transmission problems.

If you do this, be sure to clean the tube very well, or use a new one. Don't put a dirty or oily tube down the transmission dipstick tube.
 

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How come you only get out 7L? You still have to drop the small tube so you get to the bottom of the pan, maybe that's why you don't get the last L? Or are you 1L low when you change the oil? :D

ILJ, you could use this method on the AT, but still would have to use a smaller tube that would reach to the bottom of the pan. The other thing to keep in mind is that the engine sump was designed with oil evacuation in mind, and the transmission pan was not.

Take care and enjoy the ride,
Greg
 

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1922 Ford T no OBD, no ECU, no SCN
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Good it work for you this way loubapache
I don't know if that was my luck (which becomes famous on MB forum) or my persistence, but I believe both our Mityvac come with the same size tubings.
I have one tubing attached to the pump, what is I think about 3/8" and that I've got 2 smaller tubings with rubber adapters to attach to the bigger tube.
I never had illusion that the smaller tubings will make resistance, so from very first time I was pushing the big tubing into the bell end of the dipstick tube. It took some hard push to seal the connection, since the plastic tubing had a rough cut, but combination of heat and pressure made the plastic to shape to the bell end and for now it stays permanently like it.
Either way, the details how we do the job are secondary. Main thing it is WORKING
 

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I didn't notice that, Greg. You are correct.

You should connect the end of the MityVac to a piece of polyethylene tubing which fits down the tube; the bigger the better. You need to cut the end so that it does not sit flat against the bottom. I don't cut the whole end at 45 degrees, but rather start about halfway so to create a notch.

It will slow the process, but you will get a lot more out. You might want to hook up to the dipstick tube until you suck air, then use the small tube to finish it off.

Of course, that goes for a transmission too, except that if I planned ahead and bought some, I would spend the extra $1 and use a new insert tube each time. Otherwise clean it out very well. I used brake cleaner. Transmissions do not like engine oil at all, and they like dirt even less.
 

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Anyone think that this will work for transmission fluid change as well?
I dropped the tranny pan and don't recall the tube sticking out at the bottom. Meaning it ends several inches above the pan.
The pan has a drain plug, but mine was frozen and planning on dropping the pan anyway, I didn't fool with it.
Than the main issue I found doing the tranny service was thick residues at the very bottom of the pan. That stuff would never drain either way and I had to wipe it out with paper towel.
 

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Discussion Starter · #12 ·
Actually, this is the most oil I got out of this engine.

7 L is 7.4 quarts and there is some oil in the oil filter so it is very close to what I normally use for this engine (8 quarts). This is after 6500 miles (1 year).

I feel this large tube method gets all the oil out of the engine. It is like a vacuum. The small tube method is limited to the siphon (the tube must be under oil).
 

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Ah, you must be talking about your 97 L6, I guessed you were in the M112 hood.
 

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Discussion Starter · #14 ·
This is the M112 that I typically put in 8 quarts so I got 7.4 out of it by vacuuming. Then a little bit in the oil filter and maybe some oil usage in the 6500 miles. I noticed the oil level on the dipstick is a little above the half way between MIN and MAX before I vacuumed it. So I think I got all the oil in the sump out of the engine using this method. Someone else needs to verify how much they get out of their M112 using the small tube.

In the L6, I only put in 6 quarts to start then add a little more to bring it slightly below the half way between MIN-MAX, following the Mercedes TSB to minimize leakage.

You can kind of see the oil level in the Mityvac in the very last picture. It is very high in the Mityvac and as I said, I have never gotten this much oil out of this engine using the small tube method.
 

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Discussion Starter · #16 ·
For the oil to flow up the dipstick tube shouldn't the whole internal be completely in closed state? If you removed the oil filter, would air and contaminant flow through its hole?
I was thinking along the same line for a long time and that was why I never tried until yesterday.

So the answer is no. Oil vacuumed out just fine with both the oil filler cap and oil filter removed. Kajtek1 also confirmed.

It must be that the internals do not open to the filler cap or the filter housing. I am thinking that the oil pump just blocks the air so vacuum via the dipstick tube completely removes the oil. That is how the dealer do it, anyway.
 

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I dropped the tranny pan and don't recall the tube sticking out at the bottom. Meaning it ends several inches above the pan.
Thanks everyone for the ATF part especially. Dear Kajtek, I remember when I check the ATF level, the dipstick passed about 5 sharp bends before it hits something with a bong bong sound, I thought I have reached the bottom on the pan? If not, that means I can only drain a very small amount of ATF with this double tube suction method? Then, it's better to drop the pan and change everything.
 

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Thanks everyone for the ATF part especially. Dear Kajtek, I remember when I check the ATF level, the dipstick passed about 5 sharp bends before it hits something with a bong bong sound, I thought I have reached the bottom on the pan? If not, that means I can only drain a very small amount of ATF with this double tube suction method? Then, it's better to drop the pan and change everything.
You can always use a tube that is longer than the dipstick. I'll try that way the next time I change ATF.
 

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Discussion Starter · #20 ·
I have been using an electic oil extractor for both oil and ATF, very quick (about 5 minutes for oil and 3 minutes for ATF) and inexpensive - I remember I bought it for ~ $20 five years ago. It uses car battery.
Yes, that is the very first kind I used in the 80's. Unfortunately mine did not last long so I moved onto the non-electric type.
 
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