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The last time I changed my oil, I noticed a slight amount of weepage around the oil drain plug. I thought it was funny since I had never seen that before in 323K miles worth of oil changes.

Then I ran across this (somewhat dated) Honda ServiceNews note:



Hmmm... "install the new one [oil drain plug washer] with its flat side facing the oil pan". I never knew there was a "flat side" to the washer!! And in looking at an (OEM) oil drain plug washer, it is pretty hard to see any difference between the two sides. If you look really carefully though, the one side does appear to round ever so slightly compared to the other side.

What do you guys think? Is this really what the ServiceNews note refers to (put the ever so slightly flatter side facing the oil pan) or has the oil drain plug changed since 1997 and this note no longer applies? What do you guys think?

You can see in the following images that the edge of the washer is ever so slightly more rounded on one side then the other:



 

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I don't know if it makes any difference the way the washer is installed, but I've always installed it with the flat side toward the pan, just like the service newsletter suggests. I also have a habit of doing that with other washers.
 

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If it's leaking, change the washer. If it still leaks, change the drain plug and washer.
 

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Yes, I have noticed. For the engine, it doesn't leak with it installed flat side to the oil pan.

Now, with the transmission, the rounded side goes to the transmission case. For whatever reason, the trans will seep if I install the flat side to the trans case.
 

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drain plug

I've reused the washers on many occasions trans and oil pan and never had a problem.when installing new never paid attention to which side to use never had a leak.i guess under magnification you might see a rounded edge.do you think the mechanic at the dealer is putting it on right. lol:grin
 

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The difference in the sides of any NEW washer are due to the punch manufacturing process.

The flat side usually is best to go on the flatest side of the pieces, be the the underside of the bolt head or the piece to be clamped.

But the aluminum or copper crush washers get deformed, so it probably matters little which side is pan side.

I've never used a new drain plug crush washer on any car yet. I think the secret is to clean up the surface before installing the bolt. No dirt and she seals well.
 

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It doesn't matter what side goes where. The aluminum is soft enough that you just crush it a tad whenever you put it on. Both sides are gonna deform a little so it doesn't matter which side is where. Just make sure to give it a little crush and it won't leak.
 

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The regular torque value on that is 28 ft-lb, torquing to 33 ft-lb or more, you might risk pulling a thread. I learned the hard way, I cranked down too much a couple times and I pulled a couple threads. So I'm installing the Fumoto drain valve at the next oil change and will never mess with the drain plug again.

One other way to prevent leak is to use high temp locktite on the thread of the drain bolt.
 

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The difference in the sides of any NEW washer are due to the punch manufacturing process...
This is true. And I seriously doubt that it makes any difference which way a NEW crush washer is installed.

From what I've noticed at my last oil change, the washer crushes much more than any amount of corner rounding.

However, I did notice something else. The face of the oil pan is machined flat. But the underside of the plug has a profile. That shape imparts an impression in the crush washer. I can absolutely see how re-installing a USED crush washer in the opposite orientation that it was previously crushed can lead to leaks, with the profiled side facing the pan, and the flat side now facing the plug.

As for using silicone on the washer, or loctite (I hope t-rd meant the removable kind) to seal the threads, yes, I suppose this can work, but only if you remove every trace of oil before you do this. That alone is more effort than the rest of an oil change.

I'm not a fan of oil drain valves on vehicles. Too much chance of a rock leaving your oil on the road.

Anyway, now that I made myself a vacuum oil extractor, I don't plan on pulling the drain plug ever again.
 

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I'd rather drain it so that the sludge on the bottom flows out.
I'd considered that, but don't buy that argument.
If the tube does encounter true "sludge", either it sucks it up just like oil, or it's so thick that the suction action halts (which would alert me to a bigger issue, that draining through the plug might not). Either way, through the dip stick hole, I am able to access the very lowest part of the pan, which is BELOW the drain hole. I've seen that I can pull as much as a half pint more from an engine from above than I can get from below. I've also pulled the drain plug on an engine that I vacuumed from above, and could get nothing to drip. The guy in the video you linked goes into the fact that a topside oil change gets more oil out.

Anyway, my main purpose for setting my vacuum rig up was for pulling oil from things that are difficult to drain, like differentials that have a fill plug which need to be cracked open to drain, or my lawnmower or generator which need to be tipped over to drain and are filled through the same dipstick hole.
It's also good for vacuum brake bleeding, but since I now have it, I've found it wonderfully convenient for engine drains too.

I already had a venturi vacuum pump, and happened to have a forklift propane tank that's got a liquid level gauge on it (perfect for this use):


The valve on the "vapor" side lets me suck in fluids using cheap ice-maker polyethylene tubing (it doesn't collapse under vacuum, and is impervious enough for my purposes). The "liquid" side allows me to drain the tank after pressurizing it to a few PSI.

Here it is, stowed away in "lost" space in my garage, with the tubing attached before it's first use:
 

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I'd considered that, but don't buy that argument.
It's not an argument. It's an opinion. I use a 5 gallon bucket to dump my oil oil into and have been using the same bucket for 20 years. It has about 2 inches of sludge in the bottom and about 10 years ago I cleaned out another 2 inches. That's 4 inches of sludge in the bottom of a 5 gallon bucket that flowed out the bottom of my oil drain pan. I have no scientific evidence to prove that it would not come out if suctioned from above. But I have proof it came out when drained from below. I'm gonna stick with below.
 

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The rounded side of the washer is created when the machine punches the washer. It's common knowledge that the round side goes out. When the machine punches the washer, it leaves a slight raised edge around the hole of the washer. If you put this side against the pan, it simply goes inside the hole, whereas if the raised portion is out, it gets jammed in the corner of the bolt, and will take more pressure to seal.

Where I work we use hydraulic machines to torque bolts over 2000 foot-pounds. Some customers want everything by the book, even which way the washer faces.
 

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Do people really stress that much over crush washers etc?

Seriously.

I have two good torque wrenches. NEVER used them on oil pan drain bolts and NEVER had a leak, and never replaced a crush washer.

That's in probably 25 years of regular oil changes on vehicles ranging from grocery getters, sport bikes, 4x4 trail rigs, 400+ hp project cars etc etc.

The Fumoto valve thing is very handy. Loved it on my motorcycles. Never bothered on a car, except for a big block project car that sat really low in the front and I happened to have the correct Fumoto valve laying around.

I mean, I used to wrench for a living a LONG time ago, but oil changes on my 6-6 Accord, my wife's Sonata and my son's Integra are like 45 minutes from start to finish.

That includes dragging the floor jack out, the jack stands, cracking a beer, jacking the car up after it's warmed up, draining the oil, cracking another beer etc etc.

I don't remember where I read it - but pretty sure it was a tech manual or maybe an old Car Craft magazine. A standard 3/8" ratchet with a socket and no extension, puts something like 35 ft/lbs of torque on like a 9/16 bolt with a good bit of force.

I snug the oil pan bolts with a 3/8" ratchet.

However - I will admit to sometimes struggling with the oil filters. Apparently I get them too tight by using just my hand and sometimes use a oil filter socket / wrench to bust them loose.

Whatever works for you I guess.

As for sludge.....

I haven't seen any real sludge build up coming from my oil drain pans. I fill two drain pans and when full dump them into the empty 5qt oil containers (that the new oil came in) and then recycle it.

I haven't personally seen ANY sludge with any synthetic oil ever.
 

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As for sludge.....

I haven't seen any real sludge build up coming from my oil drain pans. I fill two drain pans and when full dump them into the empty 5qt oil containers (that the new oil came in) and then recycle it.

I haven't personally seen ANY sludge with any synthetic oil ever.
that's cuz you do it right and drain it out the bottom.
 

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that's cuz you do it right and drain it out the bottom.
LOL - maybe. My point was more that decently maintained modern engines, with modern synthetic oil - sludge is not going to be an issue - top or bottom oil change.

We did plenty of top oil changes on our car we raced (oval track) and now that I think about it on the big block chevy 1/4 mile car too.

No sludge.

Last sludge I personally saw from a car turned in off lease that apparently never had the oil changed. We couldn't believe the thing ran at all - much less smoothly.

The "oil" was the consistency of a thick milkshake when it first started draining.

Popped the valve cover, dropped the pan and poured kerosene through it until it came out clean. Buttoned it up, filled with cheap oil, ran it for through several temp cycles, drained again (came out fine). Filled with good oil, short change interval. After that normal. (@ 2 oil changes a year with Mobil 1 synthetic - @ 7-9K miles per change).

car still runs fine. Not sure of mileage. That was a while back.
 

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My brother had bought an old Ford Gran Torino (351ci Cleveland), and the motor blew. We were taking it apart, and when we removed the valve covers the sludge was so thick you could see the Ford imprint from the valve cover in the sludge. The guy who owned the car before had never changed the oil, just added when it got low.

The moral of the story is, change your oil.
 
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