I like Nobody's explanation... Seems reasonable.

However, I've reused these washers just like Chipperman and XV.

p.s./ XV, my '88 Prelude had the same deal with the oil washer. I think Honda's been doing this a while.

 

They work via compression.

At work, in our high pressure, high temp (plasma) chambers, we use copper gaskets. They work via compression, as copper is soft. Anyway, once the chamber is opened, out goes the gasket and in goes a new one.

Al is harder than copper - I don't think it's that much of a deformation, with those recommended torque settings. I guess someone could figure this out.

Hmm... however, the Helm manual suggets that you replace them.

Engineers know best or not, as we are always ultra conservative.

 

I actually found something about this subject on the Honda web site, guys. It's from the owner link "maintenance" section, under engine oil. Pretty interesting -- they're worried about the threads in the oil pan...:

What's a "crush washer" and why is it important to my Honda?
As a Honda owner, the crush washer you should be most concerned with is the one that must be replaced every time you change your motor oil. This crush washer fits between your oil pan and the drain plug. It is a one-time-use washer.
When a new washer is installed and the drain plug is tightened, this washer "crushes" to form a very tight seal, thereby preventing motor oil leaks without overstressing the oil pan threads.
Oil changers who are not aware of its importance may think it's OK to re-use this washer. Since it has already been crushed, it will not collapse further. As a result, the installer may overtighten the drain plug to get a tight fit. This can eventually lead to stripped threads in the oil pan -- a very expensive repair.
This is another example of why your Honda dealer is the easy choice for your service needs. Honda dealers know your Honda best.

 

Chazmo, this is not a reflection upon you but merely my commentary on Honda's quote.
Let's see if Honda has any other reason for insisting that these crush washers be replaced AND why they would want owners to come back to them for service. Well, we know why they want you to come back for service: $$$$$$$$$$$$$$$$$$$$$$$$
Now, how about those little washers than cost about a quarter each ..................... How many millions of Hondas are out there on the roads? And if each one needed a little washer every 2-4 months when an oil change is done, how much would that add up to?
Annual ADDITIONAL sales: $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
I'm sure glad that I don't over-torque my oil pan bolt and I'm even more glad that my little crush washer doesn't know that it's been re-used for about the 4th time because I'm sure that if it did know, it would be leaking now and the threads would be stripped.

 

XV,

Hey, I totally agree with you. Over-torquing the oil pan bolt would be seriously brain-damaged, I think. The spec'd value seemed well beyond "normal" tightness to begin with. I followed that torque rating (can't remember what it was) at my last oil change, and there is simply no way oil is going to leak, even at substantially less torque.

Anyway, I happened to be on the Honda site researching MSRP for '03 models (another thread). I actually found it surprising though to locate something so explicit (and topical) on the web site. There's very little else that's been of any use to me on owner link. E.g., why don't they post the TSBs there? That'll get people back to the dealers!

So, I think it's a bunch of hooey myself, XV. However, next time I'm at the dealer, I will pick up a few of these just in case I lose one (like I lost bolts from my coil cover ). Can't hurt, right?

 

[QUOTE]Originally posted by Chazmo
[B]However, next time I'm at the dealer, I will pick up a few of these just in case I lose one (like I lost bolts from my coil cover ).

 

String 'em together with a lanyard... Make a necklace... They gotta' be good for something)

Techno-jewelry!

Take it easy, XV. Stay warm up there and drive safely (as always, I'm sure). It seemed like winter started off early here in New England, but it got mild again. Always unpredictable around here.

 

I feel OK flipping it once, as long as I know it wasn't overtightened the previous time. The most beneficial crushing happens at the oil thread land surface, you'll notice when you take it off how the material got pushed in towards the oil pan away from the bolt. Flipping the washer takes advantage of this sealing twice. Beyond that you can't guarantee the original crease lines up again. I also wouldn't use it more than twice because you can develop radial cracking in the aluminum, going from the center outward. Exactly what you don't want! Aluminum is relatively ducticle, but tends to fatigue.

Just my Engineering common sense.

 

[QUOTE]Originally posted by Chazmo
[B]Take it easy, XV.

 

The crush washer is ,as many have stated the seal . The threads are straight cut , they do not seal any thing . Also the underside of the bolt head is machined flat . The washer also allows the damage of tightening the bolt , to occur in the washer , not in the oil pan ( the head of the bolt turning against the pan surface . The soft nature of the aluminum allows it to conform to any irregularities . REPLACE AFTER EVERY USE .
This is the same way Honda seals the brake line to the caliper .

brad