Crush Washers Aluminum vs Copper

autox19

autox19

True Classic
because, IMO, this forum has the smartest (some smart asses) people of all the forums I contribute to, I want to pose this question here. I have an oil leak with the oils pressure adapter on my spider. it comes with aluminum crush washers. it made me thing. which is better as a crush washer? what are the pros and cons between them?

Discuss. I will sit and learn.


Odie
 
I don't know anything, but I learned that annealing copper washers was pretty important. I reused the existing copper washers on the radiator's trans cooler connection in the 124 special several years ago. The washers looked fine, but I had a small, steady leak at one connection. Then I remembered the annealing step. Took the leaky washer out, heated it up till glowing and reinstalled after it cooled, leak gone.

A quick google search shows that aluminum needs a very controlled annealing process compared to copper. Maybe switch to copper washers since you will probably be taking it apart anyway?
 
autox19 said:
Discuss
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Aluminum crush washers cannot be reused, copper can be if it is annealed again.
Aluminum is softer than annealed copper so generally seals at least as well - it's more likely that a new washer of either type will fix the leak than that switching from aluminum to copper will.

Check the flange surfaces carefully, as even a small nick in the sealing surface will cause a leak if it extends past the outer edge of the washer. I learned this the hard way with an oil drain plug. The cure was to switch to a wider (same ID, same thickness, greater OD) crush washer.
 
I have read that if you are screwing into aluminum, such as an X1/9 oil pan, you have to use an aluminum washer.
On a steel part, like a 128 oil pan, a copper washer is correct.
 
Ulix said:
I have read that if you are screwing into aluminum, such as an X1/9 oil pan, you have to use an aluminum washer.
On a steel part, like a 128 oil pan, a copper washer is correct.
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My X aluminum oil pan came with a copper washer from the factory. The replacements I got from the Fiat dealer were also copper. The supply I have left are probably from the early 80s so I don't know if they switched to aluminum or not at some point. They don't leak so I never worried about it. My Volvo uses aluminum washers on an aluminum pan.
 
It was reading a post on this site that informed me of the existence of bonded washers. I had a slow oil leak from an oil temp sender. Tried with an annealed copper washer. still leaked. Swapped to a bonded washer. No leak. Cost 1 euro, well worth the price.
 
Alex(UK) said:
It was reading a post on this site that informed me of the existence of bonded washers. I had a slow oil leak from an oil temp sender. Tried with an annealed copper washer. still leaked. Swapped to a bonded washer. No leak. Cost 1 euro, well worth the price.
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looking it up now, well after I take one off to get the size

Odie
 
Alex(UK) said:
It was reading a post on this site that informed me of the existence of bonded washers. I had a slow oil leak from an oil temp sender. Tried with an annealed copper washer. still leaked. Swapped to a bonded washer. No leak. Cost 1 euro, well worth the price.
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I recall these being used on high pressure fuel injection lines at banjo fittings. Rather than ’crush’ they resiliently deform.
 
If a new copper washer doesn't prevent the leak, the washers with a rubber seal ("bonded") that Alex noted work great. Although there may be a slightly greater chance of the sender working a tad loose over time with one of them.

You can also put some thread sealant on the sender. The sender needs to be grounded to the block, but as it is tightened the sealant squishes out from between the threads enough to provide a signal. Exact same principle as "dielectric grease", which is actually non-conductive.

The question about copper vs aluminum is a good one. Honestly I've never seen any specific recommendations for using one over the other in any given application. I have noticed both used with various component materials by OEMs, so I never thought they were intended to be material specific. I've always assumed it was more a cost issue than anything. I believe some aluminums are softer than some coppers and vice versa, so which one will deform and seal better really depends on the specific washer in question. Personally I've always used copper because that's what I find used on high end vehicles by the manufacturers.
 
I will confess a sin of mine.

I put a thin schmeer of Formagasket (non hardening) on oil or water/coolant holding crush washers. With aged cars which have covered a few hundred thousand miles always have minor discontinuities which end up causing a leak.

I just hate leaky cars.
 
kmead said:
I just hate leaky cars.
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How do you know that the fluid is still there if there aren't any leaks?

OK, seriously, kidding aside.... that smear of non-hardening sealant is how I dealt with that nick/leak I mentioned above until I discovered that the larger OD washer worked.
 
kmead said:
I will confess a sin of mine.

I put a thin schmeer of Formagasket (non hardening) on oil or water/coolant holding crush washers. With aged cars which have covered a few hundred thousand miles always have minor discontinuities which end up causing a leak.

I just hate leaky cars.
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I like that idea. Better than putting sealant on the sender threads but with similar results. ;)
 
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