Changing Oil Plug Washer without Draining Oil

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Yep. Or would of just left the filler cap on to no avail - that shop vac is pulling a vacuum as they do.
Think I could do this alone and top off with the 4 ounces gone.
 
Depending upon the size, bottle cork might work wiht little loss of while while you swap the washer.
 
As long as you also plugged the PCV/Breather. It would still drain out fairly quickly, I think. Just glugging instead of a stream.
 
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Originally Posted By: Shannow
Originally Posted By: DBMaster
Originally Posted By: Colt45ws
No, there is air being sucked into the oil pan when you do this. You can hear it gurgling.


"Suction" is really a myth. With a vacuum cleaner you are creating an area of artificially low, or negative, pressure. The "suction" you feel is air at normal atmospheric pressure rushing in to fill the void. So, what they are doing here is preventing air from filling the void left behind by the oil.

If an airplane door is opened at altitude, things do not get "sucked" out of the airplane. They are pushed out by the higher pressure inside the plane compared to outside.


If your theory was true, taping saran wrap over the filler would do the "finger straw" thing...then the static head of the oil would have to displace enough air to ensure that a pressure head on the air inside/outside would be reached, and the oil would all be on the floor.

This is like...ohh...sucking on a straw.
DBMaster is correct. Fluids are pushed, not sucked. Vacuum cannot pull on another mass.

Sucking on a straw is only creating a low pressure zone inside your mouth, and the pressure on the surface of the fluid in the cup is PUSHING it up the straw. There is no "sucking" going on.
 
Originally Posted By: quint
DBMaster is correct. Fluids are pushed, not sucked. Vacuum cannot pull on another mass.

Sucking on a straw is only creating a low pressure zone inside your mouth, and the pressure on the surface of the fluid in the cup is PUSHING it up the straw. There is no "sucking" going on.


Yes, there is only differential pressure, however the statement made was that it's the same as a finger on a straw, which is an entirely static process.

Static process would have all of the oil on the floor.

The shop vac makes it a dynamic process...

check the change mid post

Originally Posted By: DBMaster

I think it's more like putting your finger on top of a drinking straw. Simply sealing the oil fill neck wouldn't be enough because there is already air in the engine. By using the vacuum you prevent air from replacing the lost liquid. It's like using a "whiskey thief" (look it up) on your engine.
 
Shannow, I agree with what you're saying. I read this pretty soon after I got up this morning and skimmed over it pretty quick before replying. I should have had some caffeine first.

Anyway, that being said, anyone else *not* a fan of this process? Walking around a dark room at night with a flashlight highlights how much dust you can kick up just walking around, I can only imagine how much dirt, dust, and tiny specs of grit are floating around while a shop vac is churning up the air a few feet away, with all that air and everything in it going directly into the sump of the engine.... no thanks, I'd rather remove the drain bolt, plug the hole with a clean thumb or finger to keep the oil in the pan, while I use the other hand to put the new washer on the drain bolt and reinstall it. I might lose an ounce or two of oil, but at least no infiltered dirt and dust filled air is blowing through the engine.

Its a clever process, but the more I think about it, the more it seems like not a very good thing to do.
 
Can you use an o-ring plug for all applications? These have worked the best for me. Maybe you could have the new plug ready when you take the old one out, losing a minimal amount of oil.
 
I just recently had to replace a leaking washer. It was pretty easy. Cold engine/drain pan/plug with finger/replace washer. 1/4 cup of oil. I always re-use my drain plug washers until they drip. Only have had to replace maybe a dozen In 45 years on a hundred cars over what seems like thousands of oil changes. I have never had someone else change my oil....EVER. Looking back, most of the leaking drain plugs have been on used cars I just bought. I never have, and never will use a torque wrench on a drain plug either. It simply comes down to feel, and paying attention.
 
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Originally Posted by Traction
I just recently had to replace a leaking washer. It was pretty easy. Cold engine/drain pan/plug with finger/replace washer. 1/4 cup of oil. I always re-use my drain plug washers until they drip. Only have had to replace maybe a dozen In 45 years on a hundred cars over what seems like thousands of oil changes. I have never had someone else change my oil....EVER. Looking back, most of the leaking drain plugs have been on used cars I just bought. I never have, and never will use a torque wrench on a drain plug either. It simply comes down to feel, and paying attention.


I have a '17 Mazda6 - and the OEM drain plug requires an 8mm hex key or drive bit. Torque range is 23 to 30 ft.lbs. 'Cuz these are notorious for leaking, I replace the aluminum crush washer ea. time. Never used to do this, but 'cuz this is a new car, and I don't want to strip the 8mm hex on the plug, I am playing it righter than right. I use about 25 foot pounds' torque.

There are some out there that believe aluminum crush washers are one-time use items, and that re-use will cause leaks, and then overtightening the plug to quell leaks will strip the drain plug (or the head of the drain plug). Others say that copper crush washers can be re-used, provided you use a propane torch to anneal them to "full-soft" again. I have never done this, however.

I want to replace the plug with an external hex Dipple or Gold rare earth magnet drainplug.
 
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The absolute best washer is a thick copper one. The ones I made worked great. Annealing is a minute with a torch an a plop into some old oil.
 
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