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I just know this is a subject near and dear to all of us . . . .
Let's be honest now; how many of us actually replace the Crush Washer (Part Number 94109-14000) when changing the Engine/Transmission Oil and/or the Differential Oil?
The Service Manual (see below) does say; "Install the oil drain bolt with a new sealing washer and tighten it."
Now really . . . . why a new Sealing Washer? The old one looks perfectly fine and reusing it doesn't seem to invite any certain disaster.
So anyhow, I thought I'd see just how much "sealing" this Crush Washer does. It turns out that it actually does engage and function as a fairly well designed seal between the Bolt and the Case.
The attached picture tells a story. The old Crush Washer is on the left, a new Crush Washer is on the right. First notice how the old Crush Washer has grooves in it. This indicates that the Crush Washer has deformed ever so slightly to accommodate any irregularities in the surface of the Case and/or the flange of the Bolt. Of greater interest is that this Crush Washer actually does "crush". I have a handful of new Crush Washers and they all measure exactly 0.080" thick. The used Crush Washer shown here measures 0.074" thick. This represents (not counting the grooves on the used washer) a minimum crush of 0.006" This is actually fairly significant. Metals have elastic properties. While under compression a metal will exert a force in the direction opposite to that which is compressing it. The 0.006" difference tells me that the torque specified for tightening the Bolt exceeds the elastic limit of the metal the Crush Washer is comprised of. The good news is that when a new Crush Washer is used its elasticity helps to effectively seal the opening. The bad news is that once it's elastic limit has been exceeded per the torque specification its sealing capability has been seriously compromised if it is reused.
Based on personal experience, having reused these Crush Washers more often than I'd care to admit (or boast of) the risk one runs is probably not terribly great. On the other hand, Honda is correct, in as much as to minimize the possibility of any failures and or leaks or weepage, one probably should replace the Crush Washer.
You may now file this away under the heading: "Goldwing Trivial Pursuit" . . . . :nerd:
Let's be honest now; how many of us actually replace the Crush Washer (Part Number 94109-14000) when changing the Engine/Transmission Oil and/or the Differential Oil?
The Service Manual (see below) does say; "Install the oil drain bolt with a new sealing washer and tighten it."
Now really . . . . why a new Sealing Washer? The old one looks perfectly fine and reusing it doesn't seem to invite any certain disaster.
So anyhow, I thought I'd see just how much "sealing" this Crush Washer does. It turns out that it actually does engage and function as a fairly well designed seal between the Bolt and the Case.
The attached picture tells a story. The old Crush Washer is on the left, a new Crush Washer is on the right. First notice how the old Crush Washer has grooves in it. This indicates that the Crush Washer has deformed ever so slightly to accommodate any irregularities in the surface of the Case and/or the flange of the Bolt. Of greater interest is that this Crush Washer actually does "crush". I have a handful of new Crush Washers and they all measure exactly 0.080" thick. The used Crush Washer shown here measures 0.074" thick. This represents (not counting the grooves on the used washer) a minimum crush of 0.006" This is actually fairly significant. Metals have elastic properties. While under compression a metal will exert a force in the direction opposite to that which is compressing it. The 0.006" difference tells me that the torque specified for tightening the Bolt exceeds the elastic limit of the metal the Crush Washer is comprised of. The good news is that when a new Crush Washer is used its elasticity helps to effectively seal the opening. The bad news is that once it's elastic limit has been exceeded per the torque specification its sealing capability has been seriously compromised if it is reused.
Based on personal experience, having reused these Crush Washers more often than I'd care to admit (or boast of) the risk one runs is probably not terribly great. On the other hand, Honda is correct, in as much as to minimize the possibility of any failures and or leaks or weepage, one probably should replace the Crush Washer.
You may now file this away under the heading: "Goldwing Trivial Pursuit" . . . . :nerd:
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