Can somebody tell me why on the 3.6 tdv8 it is important to renew the two sump plugs with every oil change?
All my previous car had the sealing washer changed, but not the plug aswell.

some oil filters come with sump plugs, if yours doesn't then it would be worth getting two just in case one or both removed plugs are knackered..... ... - .- -.




Y. O. L. O.
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I still don't understand why they are a throw away item, never replaced a sump plug on any other car.

Its not the bolt, but the copper ring that fits around it making the seal between the bolt and the sump. They are supplied annealed ( softened ) so that when the bolt tightens, the copper deforms to match the shape of each surface. Copper like most metals / alloys work hardens ... so when you re-use the bolt *in theory* the copper ring will have hardened and not provide as good a seal .

[aside] I wonder if the soft copper also acts as a thread lock effect as well as sealing?? i.e. gripping the bolt and preventing it from turning [/aside]

Anyhows ... you can anneal the existing copper ring by picking if off and heating it till its glowing for a short while then letting it cool down in air. That in theory will re-soften it a bit just like a new one.

I've used heatguns and MAP gas blow torches in the past ... as well as just using the bolt that came with the filter !  V8 or else ...

The sump plugs that arrived don't have a metal washer, it has a rubber O ring fixed in the plug, I now understand why it is to be replaced.