Crush washers.. Al vs Cu

[2K2AcuraTL]

For oil or trans drain plugs...
Honda / Acura used aluminum washers.. my local dealer is across town, so I go there only when I have to...

So poking around on Amazon.. i can get a 10pk [or more ] of copper washers..

Is there any reason, in your opinion, NOT to use Copper washers..??
Thanks
J.

 

[DuckRyder]

You can get the AL ones on amazon too.

 

[DriveHard]

I use copper...if you look at the hardness scales, it is slightly softer, so it should seal better.

 

[Bud]

Use either one. I buy my AL ones on Amazon for my Honda.

 

[knerml]

Will the Cu set up galvanic corrosion potential with the aluminum casing and/or steel plug?

 

[Chris142]

Originally Posted by knerml
Will the Cu set up galvanic corrosion potential with the aluminum casing and/or steel plug?

I have never seen that happen. I assume that there is enough oil around to prevent that.

 

[MasterSolenoid]

Question: Are Crush Washers 'regular' looking or designed to collapse ?

Both photos (from Internet) are listed as being Crush Washers

 

[RooflessVW]

Originally Posted by MasterSolenoid
Question: Are Crush Washers 'regular' looking or designed to collapse ?

Yes.

 

[4WD]

Originally Posted by Chris142
Originally Posted by knerml
Will the Cu set up galvanic corrosion potential with the aluminum casing and/or steel plug?

I have never seen that happen. I assume that there is enough oil around to prevent that.


Used copper (eBay assorted) on aftermarket transmission pan drain kits for years ... no reaction between dissimilar metals ...
Will do this on my newer units soon ...

 

[PimTac]

Originally Posted by MasterSolenoid
Question: Are Crush Washers 'regular' looking or designed to collapse ?

Both photos (from Internet) are listed as being Crush Washers

The bottom pic is a crush washer. The top pic is just a regular washer.

 

[Trav]

Originally Posted by DriveHard
I use copper...if you look at the hardness scales, it is slightly softer, so it should seal better.

Hardness depends on the type of copper or aluminum and the hardness test used, I doubt both are pure but rather an alloy. On the Vickers scale aluminum, is softer than copper with Aluminum 167 MPa and Copper 369 MPa. From experience aluminum seals better at lower torque, most copper ones are not "dead soft" copper and harder to seal.

http://periodictable.com/Properties/A/VickersHardness.v.log.html

 

[Trav]

Originally Posted by MasterSolenoid
Question: Are Crush Washers 'regular' looking or designed to collapse ?

Both photos (from Internet) are listed as being Crush Washers

Its terminology, due to the soft nature of these both can be considered crush washers due to the fact they both deform (crush) under compression, if they were steel the top ones would be flat washers.

 

[Hall]

Originally Posted by DriveHard
I use copper...if you look at the hardness scales, it is slightly softer, so it should seal better.
Honda uses aluminum-based crush washers. Is Al vs Cu cost a factor ? Maybe.... Do they base their choice more on functionality ? Probably. Copper might be too soft as well.

 

[JohnnyJohnson]

Kind of like electrically which wall switches are more efficient white or dark colored.

 

[Hall]

Originally Posted by PimTac
The bottom pic is a crush washer. The top pic is just a regular washer.

Have you ever seen a used crush washer like the ones shown in the top pic ? They definitely 'crush' or deform. A regular washer is typically made of steel and is much harder. I think you'd have a hard time crushing a steel washer in between a drain plug and a stamped metal oil pan without doing more damage to the oil pan. An aluminum crush washer deforms slightly under normal drain plug torque (below 30 ft/lbs).

 

[2K2AcuraTL]

I wouldnt dream of using steel washers... probably strip the threads off the pan before you'd get a good seal..

 

[PimTac]

Originally Posted by hallstevenson
Originally Posted by PimTac
The bottom pic is a crush washer. The top pic is just a regular washer.

Have you ever seen a used crush washer like the ones shown in the top pic ? They definitely 'crush' or deform. A regular washer is typically made of steel and is much harder. I think you'd have a hard time crushing a steel washer in between a drain plug and a stamped metal oil pan without doing more damage to the oil pan. An aluminum crush washer deforms slightly under normal drain plug torque (below 30 ft/lbs).




I saw Trav's comment and now understand the concept.

To add to this, it's my thought that there is a difference between crush and deform. A cheap steel washer will deform. I guess the correct term is a flat washer.

Another consideration might be that the oil pan may not be steel. Are aluminum pans commons nowadays to save weight? I've heard of plastic pans as well. It might seem trivial but using the correct washer would be more important in these cases. I've seen a few pans where the surface around the hole was really marred up. More chances of leakage in that case.

 

[Hall]

Originally Posted by PimTac
...it's my thought that there is a difference between crush and deform. A cheap steel washer will deform.
There are probably technical definitions but my thoughts are: 1) Even a cheap steel washer will be pretty hard to crush (flatten, make thinner) against a stamped metal (aluminum, steel, etc) oil pan. 2) You can crush a proper 'crush washer' in these same situations. 3) You can deform both a steel, aluminum, or copper crush washer. By deform, I mean change it's shape from " | " to something slightly like " ( ". Make sense ?

 

[Trav]

Steel washers can be soft but not soft enough to use as a seal as it does not embed or deform very well especially at low torque. Aluminum pans save weight and are more rigid allowing manufacturers to use sealing methods like RTV and automation to apply it with greater reliability instead of a gasket, the problem with them and plastic pans is usually thread strength is low compared to steel.
Some use steel thread inserts especially on the plastic but most aluminum do not, for this reason a lower torque is spec'd. To achieve proper sealing the crush washer is very soft aluminum with a wide surface area, using a washer harder than the pan can result in marring of the pan sealing surface as you have seen.

There are some steel washers with rubber inserts, nylon, fiber and all work but IMO its best to use what the OE used on the pan, you can buy it from another source but keep it the same inside/outside diameter and material. Once the pan sealing surface is damaged you will always have a hard to seal pan.

 

[ARCOgraphite]

.
No Torquing spec - crush washer till crushed then stop.

Flat malleable washer = would use a torque spec - or as much you can put on it with a 10" ratchet handle