Sump Plugs - some dealers don't replace them

[prise]

I picked up the parts to do an interim oil change on my 118TSI (probably not necessary but something I've decided to do just for the first service interval). Everything was OK except they had given me a copper sump plug washer instead of a replacement plug. When I queried this at the spare parts counter I was told "we cut off the washer and replace it with a copper washer - it provides a better seal".

On getting home and on closer examination I could see that the original plug was a passivated (zinc coated?) steel plug with an aluminium washer and the sump was aluminium. Now this all makes sense from a corrosion point of view so I was reluctant to use a copper washer in combination with an aluminium sump which would leave the aluminium around the washer vulnerable to corrosion.

In the end I played safe, stuck with the procedure in VW's erwin and shelled out $5 for a replacement plug, fitted it after the oil change and torqued it to the specified 30Nm. However in the process I discovered that the replacement plug had a 19mm head whereas the factory fitted plug had an 18mm head!!

I have subsequently queried the use of copper washers with another dealership and was told "we always use a replacement plug". I'm interested now to know whether the fitting of copper washers is common or just something a particular dealer does. Given the potential for galvanic corrosion. I'd be surprised if it was endorsed by VW although you would probably get away with it in Australia given we don't salt the roads in winter like many european countries do.

For reference the washer and plug purchased had the following part numbers:

Copper sump plug washer N0138492
Sump plug with aluminium washer N90813202

[Jmac]

I use a New plug every time, no excuse
Cheers
Jmac

[Preen59]

Mate, it's a sump plug. That means you will get a little oil on it preventing such things. Unless you want to drive it through salt water 8 hours of the day, i think you'll be OK.

It's really, reallllllllllly low on the list of things to worry about.

Sorry if that seems blunt, but i'm being honest.

[prise]

That means you will get a little oil on it preventing such things

The one I removed was dry as a bone on the outside - not a hint of any oil seepage.

[boris]

Hi Prise,

What dealer did you go to?

I would always recommend renewing the plug. Im pretty sure the factory does too?

Cheers,

Boris

[Guest1306]

Both Copper & Aluminium are NON FERROUS metals, which in short means when coming into contact with each other there is no corrosion as a result of Iron (Neither contain Iron)

I somehow doubt that Volkswagen would endorse its dealers using a Copper washer unless it was up to the manufacturer’s high standard.

[brad]

I agree with Preeny.

Considering you are going to get the oil changed in another 7500km, how much "corrosion" is going to occur in that period? They've used a genuine VW part, so I can't see what the issue is...... and if it all goes to poo then it's a warranty/dealer problem.

Then again, I also disagree with doing an early oil change during the 15,000km run-in period, so my lack of care-factor probably doesn't sit well with you anyway.

Just out of interest, when you replaced the plug, how much oil came out & what did you do with that oil? Do you regard yourself as a "suitably qualified person" to carry out the operation of removing or replacing the sump plug?

[Corey_R]

Both Copper & Aluminium are NON FERROUS metals, which in short means when coming into contact with each other there is no corrosion as a result of Iron (Neither contain Iron)

I somehow doubt that Volkswagen would endorse its dealers using a Copper washer unless it was up to the manufacturer’s high standard.

In watercooling, using cooler and aluminium in the one system is a HUUUUUUUUGE no-no because although neither copper or aluminium are corrosive on their own, when in the one system they are very corrosive. You can use additives and chemicals to reduce this effect, but it's best to just avoid using a mix of metals in the first place.

But as I said, that's from my first hand experience with water cooling from the IT industry. I've no experience with oil systems

[Guest1306]

Well I stand to be correct, but I believe the coolant used in motor vehicle engines is made up of de-ionised water, which would negate the corrosion.

[Corey_R]

Very likely! In the late 90's before water cooling became an accepted thing to do (again), we just used to use to mix car coolant with filtered water to reduce the chances of issues.... Now that water cooling is rather popular, entire systems are aluminium or copper, and there is dedicated coolant fluid or concentrates available.