Engine sump-plug washers

[alldownwind]

Here's a question for all you engineers out there.
I have been plagued by a persistent oil drip from the sump plug on my 9-year old V-P 2020, which began this year despite the plug never having been removed so far as I know - green paint was intact all round it.
The original washer was, I found, a 'Dowty' washer, which has a rubber (or neprene?) insert to seal round the bolt threads. Couldn't find one of these to fit, and a Volvo dealer confirmed that they are no longer used on this engine. He gave (yes, gave!!!) me some new copper washers.
But fitting one of these, and tightening up as far as I dared, did not stop the leak.
I've ended up fitting a fibre washer which has done the trick.
Question is - is a fibre washer OK to use for this purpose, or will it fall apart?

 

[morgandlm]

A fibre washer will be fine if the sump plug is to be left undisturbed but will quickly deteriorate each time the plug is removed.
Morgan

 

[VicS]

Yep I had to use a fibre washer when I changed the oil in a friends MD11C. The original was aluminiun and had corroded to the point where it fell apart when removing the drain plug.

I dont like the idea of copper washers in a boat engine because that could lead to corrosion of the surrounding iron or steel crank case or sump . At least with the aluminium one it is that which corrodes so can easily be replaced unlike the crank case or even sump.

I suggest that you always fit a new washer or at least have one handy if you use fibre ones. The Ford car I had some years ago had a plastic washer. I changed the oil every 6k miles for over 100k but always reused the same washer. One of those would be ideal if one could be found the correct size.

Copper washers must be annealed before use or reuse if there are used. Still using the 25year old one in my Volvo car.

The alternative is to suck the oil out via the dipstick hole like the professionals do. They don't care that they ony get about 3/4 of it out. We pump most out but always drain the remainder via the drain plug.

 

[alldownwind]

Thanks everyone.
Mystery is why the old washer started leaking - it was really quite a bad leak. As I said, it hadn't been touched to my knowledge - I'd always sucked out the old oil.
Anyway, problem solved, new fibre washer to be fitted each time plug removed. Many thanks, all.