Oil change? Is a New sump plug and washer essential?

[vwcabriolet1971]

I would agree that in vehicles that have been serviced by some garages & non-caring owners who do not change the plug ,the chances of the plugs being dropped , not cleaned and not checked are quite high and I would guess that this is the reason why VW recommend them to be renewed. But for the careful owner who does all his own oil changes & has time to spend to clean and check plugs , renewal is not IMHO necessary.
The majority of the damaged bruised/burred thread plugs cannot be seen easiily with the naked eye, it needs an at least a 10X eye glass to see it. In most screw manufacturing processes, completed screws are continually dropped onto each other causing thread damage. Unless special precautions are made in the process and each screw is protected in a similar fashion to that of spark plugs ( cardboard collar around the thread) , then damage, however slight, will occur.

[DennisD_]

I would recommend replacing the sump plug washer every time you perform an change the oil. I actually use a Femco oil drain plug, the plug only installed once and you don’t have to change the washer every time you perform an oil change. Besides this you avoid damage to the thread and to the sump itself. http://www.femcodraintechnology.com/

[edwardsj]

Whenever I have to disturb a sump plug, I like to have a fresh washer to go back on - preferably a collapseable copper one.. very reliable sealing.

But,

Unless there is serious oil contamination (fuel, water, etc), I do an oil change by sucking it out through the dipstick. You won't get 100% out, but you don't get complete removal by bottom draining either. The solution to pollution is dilution... Much quicker to do this way, and you don't have to worry about sealing up the sump. Very clean method too....

[Teflon]

I got a free service on my wife's car at my local VW dealer. Long story, but it was by way of compensation. Anyway... picked the car up, drove home and noticed oil leaking on my drive. So I went back and they fixed it. Methinks my free service didn't include a new sump plug and more likely, the old one got dropped. I was absolutely on tenterhooks at the next (indie)service in case all they'd done was heave on a spanner until the drip stopped, I expected to end up with a new sump.

Whoever decided to make the seal dependent on an aluminium thread is halfwit.

[zollaf]

on these sump plugs that don't use a washer to seal, you can add a copper washer. this ends the problem once and for all. its a steel bolt thats tightened to 25nm, thats not tight at all, certainly not tight enough to damage a thread. the threads get damaged when people don't replaced it and try to stop it leaking, by overtightening it. add a copper washer and jobs done, a sump plug for life.

[Crasher]

Whoever decided to make the seal dependent on an aluminium thread is halfwit.

The sump is made of aluminium to make the block more rigid but it has been a pain due to the thread failing and impact damage so now the sump is often two piece with an ally upper and stamped steel lower.

[vwcabriolet1971]

Most modern VAG models have captive washers on the sump plug so you cannot fit a copper washer easily . On models with alum sumps the the sealing is done by the soft alum threads deforming to the steel plug threads.