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180720 km on the clock, time for an oil change today.
Every thing is normal.
I changed the filter, fuel filter and the seal around the drain plug.
Time for thightening to 30Nm as per VW Workshop Manual.
And here is the issue.
Oil sump threads are gone. I hand tight first and after making contact, set my torque wrench to 30Nm and start the final torque...that never came.
I don't know what happened. The seal (metal one) did his job of deforming itself but the drain plug fail (or oil sump threads failed).
Torque was increasing as normal and from a second, bolt became loose...
I had a cold sweat.
PXL_20250414_082034756 (1).jpg (3.1 MiB) Viewed 2036 times
I finish my job, put the 4L of oil required and return back to home (40min of driving).
No issue at all, no leaks.
You should be able to buy a "thread repair kit" for that, which will mean drilling and tapping a bigger hole in the alloy sump, fitting a threaded insert - probably with locking compound on its male thread, then using a new sump plug and washer.
Now, going by my official VW workshop manual, at the first oil change, the original "plug with captive washer" gets thrown in the bin, and a different type of sump plug gets fitted along with a "use once" rolled washer.
I've forgotten what our local VW dealership in UK did to my wife's August 2015 1.2TSI 110PS engined Polo, but I have always used the correct drain plug and correct rolled washer - but I did initially only buy 2 of these correct drain plugs, and swopped them over at service time - fitting a new sealing washer every time. Then, maybe at the year 7 or year service 8 service, I noticed that the plug could be initially easily unscrewed before becoming tighter as it was being removed, so at the next oil change, I cleaned up the threads in the alloy sump with a correct size tap, quite a few small bits of alloy were removed, but the sump plug fitted more easily - ie smoothly.
At the next service, I fitted a new drain plug and threw away the 2 that I had used previously - I'll probably buy another new one, at each of the pre-paid services within the initial new car 3 year warranty period, the "scope of work" work sheet that I demanded that I was given by that VW dealership, showed that a new plug and a new washer was being fitted at every service - how true that was I can't say, so maybe VW Group discovered that re-using steel drain plugs in alloy sumps was now not a good idea, and it was me repeatedly re-using the same 2 plugs that caused a build up of damage to the alloy sump threads, who knows!
For context, I have had 2 VW cars in the past that both had alloy sumps and tended to re-use the "drain plug with captive washer" a few times without ever ending up with problems with the sump drain plug threads, so what has changed?
Also, I am very fussy about checking the condition of the threads on all new steel sump drain plugs I have bought - due to discovering dinged/damaged threads due to the way they end up being handled after being manufactured, used small files to remove any damage before using them for the first time.
I bought a bag of maybe 20 correct size/type sump drain plug sealing washers on ebay - from China, probably where VW Group spares warehouses sources them from, and have had no problems with them when used on my wife's 2015 1.2TSI 110PS Polo, for my 2011 Audi S4, I continued to use up the genuine VW Group ones, then bought some from ECP - their offering, from a proper source are crap, so I've changed over to using the China sourced ones for my car as well!
Edit:- I think that sealing a new sump "perfectly" could end up be a bit challenging, so I'd stick with repairing the threads on that sump.
RUM4MO wrote: ↑Mon Apr 14, 2025 4:13 pm
You should be able to buy a "thread repair kit" for that, which will mean drilling and tapping a bigger hole in the alloy sump, fitting a threaded insert - probably with locking compound on its male thread, then using a new sump plug and washer.
Now, going by my official VW workshop manual, at the first oil change, the original "plug with captive washer" gets thrown in the bin, and a different type of sump plug gets fitted along with a "use once" rolled washer.
I've forgotten what our local VW dealership in UK did to my wife's August 2015 1.2TSI 110PS engined Polo, but I have always used the correct drain plug and correct rolled washer - but I did initially only buy 2 of these correct drain plugs, and swopped them over at service time - fitting a new sealing washer every time. Then, maybe at the year 7 or year service 8 service, I noticed that the plug could be initially easily unscrewed before becoming tighter as it was being removed, so at the next oil change, I cleaned up the threads in the alloy sump with a correct size tap, quite a few small bits of alloy were removed, but the sump plug fitted more easily - ie smoothly.
At the next service, I fitted a new drain plug and threw away the 2 that I had used previously - I'll probably buy another new one, at each of the pre-paid services within the initial new car 3 year warranty period, the "scope of work" work sheet that I demanded that I was given by that VW dealership, showed that a new plug and a new washer was being fitted at every service - how true that was I can't say, so maybe VW Group discovered that re-using steel drain plugs in alloy sumps was now not a good idea, and it was me repeatedly re-using the same 2 plugs that caused a build up of damage to the alloy sump threads, who knows!
For context, I have had 2 VW cars in the past that both had alloy sumps and tended to re-use the "drain plug with captive washer" a few times without ever ending up with problems with the sump drain plug threads, so what has changed?
Also, I am very fussy about checking the condition of the threads on all new steel sump drain plugs I have bought - due to discovering dinged/damaged threads due to the way they end up being handled after being manufactured, used small files to remove any damage before using them for the first time.
I bought a bag of maybe 20 correct size/type sump drain plug sealing washers on ebay - from China, probably where VW Group spares warehouses sources them from, and have had no problems with them when used on my wife's 2015 1.2TSI 110PS Polo, for my 2011 Audi S4, I continued to use up the genuine VW Group ones, then bought some from ECP - their offering, from a proper source are crap, so I've changed over to using the China sourced ones for my car as well!
Thank you for your feedback.
And yeah you are right, here is the PDF from VW:
Capture 1.png (202.27 KiB) Viewed 1994 times
And I have this drain plug: N90288901
vis-bouchon-de-vidange-d-huile-m14x1-5x16.jpg (86.56 KiB) Viewed 1994 times
but there is aslo these one, same part number:
vis-bouchon-de-vidange-d-huile-m14x1-5x16 (1).jpg (90.13 KiB) Viewed 1994 times
So, I'm sure it's not the one from factory, it's the second type, shorter or something else.
And with it, the crush washer. Always renewed.
"how true that was I can't say, so maybe VW Group discovered that re-using steel drain plugs in alloy sumps was now not a good idea, and it was me repeatedly re-using the same 2 plugs that caused a build up of damage to the alloy sump threads, who knows!"
If it's correct, the WorkShop Manual is wrong so, and I have followed it.
Because I aslo notice that I could screw it by hand but after few turn (3-4) it's started to be more hard. But I was aware because I had the same "issue" during the last few oil change.
Mine was never replaced by the dealership.
I only became aware of the different sump plug when I noticed a leak.
The captive washer plug always had a tight spot to it when fitting or removing.
I bought 2 different sump plugs from my aftermarket VW part supplier. They too were unaware that those need changing.
The non-captive washer plug they gave looks like the same thing fitted to my mk1 Golf.
Much shorter than the original. If it's correct, who knows. Should be since I went in with part numbers.
I fitted the replacement captive washer during that service though as I completely forgot to actually buy the copper crush washers.
It will be going in on the next service.
As for repair, you can probably find a replacement sump at the breakers/junkyard. Sealing it is the problem. Took me a while to get hold of Permatex 765-1189 after buying several recommended sealants which then become non-recommended sealants. You need a proper anaerobic sealant on things like the sump. I needed it for a oil separator replacement. It's probably easier where you are to order Permatex, but it's become difficult where I am.
Only issue I have with tapping it for a larger size plug is where does the swarf go?
Then again...
If your car is anything like mine and consumes enough oil for me to replace all of it between oil changes then, well, just weld it up since it would've done an oil change by the next time the service comes round.
You can also change the oil by pumping it out of the thin tube on the dipstick. It's a tactic that many companies prefer to avoid such issues, like you.
Ι don't prefer it, but in your case it will certainly save you from extra work at the next oil change until you decide what to do.
Some of those pumps going into the dipstick actually do remove more oil. Usually the sump plug is a little off the lowest point of the sump which means some oil is always left behind.
Look where the lower edge of the threads are in relation to the bottom surface of the sump. That's still all holding some oil. Some sumps have a very high plug so there can be quit a bit of oil in there.
With a thin enough tube you can get down below that level and get the remaining oil out.
If you really want as much out as possible, then feed a small tube into the drain hole at the bottom and suction out what is left.
Real issue is those oil suction pumps are just another costly tool to occupy valuable garage space.
Still can't believe your one stripped out with such low torque. Must've been eating away at the metal for a few oil changes. Steel pan would be nice. Never an issue on any car I had with a steel pan.
2226 wrote: ↑Tue Apr 15, 2025 2:26 pm
Some of those pumps going into the dipstick actually do remove more oil. Usually the sump plug is a little off the lowest point of the sump which means some oil is always left behind.
Look where the lower edge of the threads are in relation to the bottom surface of the sump. That's still all holding some oil. Some sumps have a very high plug so there can be quit a bit of oil in there.
With a thin enough tube you can get down below that level and get the remaining oil out.
If you really want as much out as possible, then feed a small tube into the drain hole at the bottom and suction out what is left.
Real issue is those oil suction pumps are just another costly tool to occupy valuable garage space.
Still can't believe your one stripped out with such low torque. Must've been eating away at the metal for a few oil changes. Steel pan would be nice. Never an issue on any car I had with a steel pan.
At least on this oil sump, the drain plug is at the lowest point.
Each time I drained the oil, you can be sure I can put 4L of oil without exceedind the "Max" line on the oil dipstick.
And for oil drain, I can wait between 15-20min, te be sure to remove a maximum of nasty oil.
Aluminium is a s**t metal, at least here. My main issue was the fact I was still using the same drain plug and according to some people, it's better to change it to avoid this kind
of *pricey* situation.
I keep the car lifted high when draining. It helps.
I'm sure not all of it comes out, but you are right it is pretty close to the bottom. My other cars, not so much.
Some American cars I've seen can have almost a quart of oil not removed.
Wonder if they went with aluminium for cost or for maybe something like heat dissapation or perhaps easier to manufacture baffling.
I have on my shopping list a Fumoto plug or something similar. A plug where you don't have to unscrew it all the time. People are scared of these, but I've seen them used on offroad vehicles that see heavy abuse and they haven't broken off or leaked. There's a few different varieties and brands out there for those. Also ones that don't have the "tap". Might be worth it. They drain slow though.
I've always raised the front of my cars to make sure more of the oil drains out.
On the subject of getting rid of the swarf after re-tapping the drain plug hole, just add some fresh oil into the engine while the drain plug is still out and that will flush any swarf out through the open drain plug hole.
Correct drain plug is N 902 889 01 and the correct rolled sealing washer is N 013 815 8, when anyone calls a sealing washer a "copper washer" I think about thick solid copper washers - this is not the correct type for these engines, a rolled maybe alloy washer is what is needed to make sure that you seal the drain plug using the correct tightening torque.
2226 wrote: ↑Tue Apr 15, 2025 2:26 pm
Still can't believe your one stripped out with such low torque. Must've been eating away at the metal for a few oil changes. Steel pan would be nice. Never an issue on any car I had with a steel pan.
Strangely or not, my old 2011 Audi S4 has an alloy bottom end and a steel plate covering that, is that means that it effectively has a steel sump at least where the drain plug screws into - it uses the same rolled sealing washer as the 6C Polo uses after its first oil change.
Many new vehicles seem to have that design. A upper sump or lower crank housing with a lower steel sump. Easier to repair too if you manage to hit something.
