Copper washer on coolant drain plug

[Ozzieflyer 15]

Hi All,

Just wanted to know the thoughts of you all in relation to copper crush washers vs aluminium crush washers.

I recently flushed my radiator coolant and was given a aluminium crush washer to use.

I have read that most of the comments say that you don't change them but I always change my crush washer due to the small price of them.

 

My question is does it matter whether it is a copper one or the aluminium on the coolant drain plug?

 

Cheers,

Oz.

 

Edited May 28, 2022 by Ozzieflyer
Clarification of the location for the washer

[davebike 943]

Hi

Probibly not I prefer to use alloy but the only issues are that ally is softer and I think the can be dissimilar metal corrosion with copper but unlightly to be an issue

 

 

[Andy m 23,543]

There is practically no difference. Both are soft metals that will conform to surfaces and seal them, both will corrode until the surface is oxidised. 

 

Classic bike nut jobs will go crazy annealing the copper ones because they have to much time on their hands. 

 

Andy 

[Jamesc 3,655]

Speaking about corrosion, we use aluminium anodes at work to try and slow down the corrosion rate of carbon steel vessels & structures. The aluminium gets consumed relatively quickly, if we change them to copper then the anodes wouldn't be consumed in the same way, but the carbon steel they are protecting would rust very slightly faster than usual...

 

https://en.m.wikipedia.org/wiki/Galvanic_corrosion

 

There's a table in the above (anodic index) & recommendations for how far apart the two metals can be on the scale etc

 

On a painted steel radiator I wouldn't think it makes much odds, whatever keeps the water inside works.

 

 

 

Edited May 28, 2022 by Jamesc

[Xactly 5,419]

2 hours ago, Andy m said:

There is practically no difference. Both are soft metals that will conform to surfaces and seal them, both will corrode until the surface is oxidised. 

 

Classic bike nut jobs will go crazy annealing the copper ones because they have to much time on their hands. 

 

Andy 

Only need to anneal if re-using…

[Foxy 4,339]

7 hours ago, Andy m said:

There is practically no difference. Both are soft metals that will conform to surfaces and seal them, both will corrode until the surface is oxidised. 

 

Classic bike nut jobs will go crazy annealing the copper ones because they have to much time on their hands. 

 

Andy 

Yes us old folks know that copper is the best way, in the same way that we know there is nothing to beat slate for damp proofing. Sometimes old, aka classic is

 still the best.

[Ozzieflyer 15]

Thanks for the replies to this topic. 
You have been very helpful. 

[Rev Ken 6,331]

On 28/05/2022 at 09:42, Xactly said:

Only need to anneal if re-using…

And it is a simple and quick process if you have a gas cooker! (Or a BBQ)