Aluminum and copper sealing washers

[menesesjesse]

All
What is the difference as far as application when it comes to these 2 materials.  I have seen things mixed and matched but was wondering if there are specific no no's when it comes to using these washers. An example would be the coolant pipe that comes off the fwd part of the head.  Would both materials do or is the aluminum the only thing that should be used(thats what came off of it)  Thanks
Jesse

[wwheeler]

Copper has a higher hardness (370 MPa) vs. aluminium (167 MPa) on a Vicker's scale. I think copper would be used for higher torque applications. Aluminum deforms easier (seals with lower torque) but also galls easier. I had an aluminum seal ring pit on the sealing surface because the surface on the mating part had some roughness. Sure enough, that seal ring leaked as soon as it was installed. Where seal rings are used, mating surfaces must be very smooth.

I have bought several sealing rings from the Classic Center and I am not sure there is a definite pattern. Is there a compound you can put on the seal ring prior to installation that will increase the sealability?

Sorry couldn't be more help.

[waqas]

There is definitely a pattern, but I'm not sure about the reasons behind the choices.

For example:

• The fuel line/hose fittings use aluminum washers (around the fuel filter housing and damper)
• The fittings around the power steering box all use copper washers
• The oil-pan drain bolt uses a copper crush washer
• The fuel injectors use copper washers
• The valve cover bolts use copper washers
• The cooling bypass line banjo bolts use aluminum washers
• I don't remember whether the radiator and oil/water heat exchanger drain plugs use copper or aluminum

[ja17]

Hello Waqas,

The valve cover bolt washers are actually copper crush washers (composite). The aluminum and solid copper seal rings can usually be interchanged without consequence.

 One of the most questioned applications is in the oil filter kit.  The large copper crush washer is for the drain plug on the oil pan.  The solid copper washer is for the drain plug on the oil cooler, and the steel washer is for the bolt on the oil filter canister.

Some cars have the new style oil pans (produced after W113 production ended).  These new oil pans have a smaller drain plug bolt.  The solid copper seal ring can be used for this drain plug instead of the oil cooler drain plug.

[wwheeler]

Most seal rings are used in several places throughout the engine and transmission. I received a tip from the Classic Center regarding seal ring part numbers. Most MB #s begin with 007603 (not all though) and then the next three numbers denote the inside diameter in millimeters. I am not sure what the last three numbers mean.


     

[menesesjesse]

All
Thanks for the guidance.  i learn new things daily.  I have puchased more seals just in case I got one wrong.  Thanks
Jesse