There are two sealing surfaces, both anular, sump-to-washer and washer-to-underside of bolt head.

 

Wherever threaded fasteners are part of a sealing component (other than where you have tapered threads) there's always something like a seal washer, o-ring, sealant on the threads, PTFE tape etc.

Edited 18 May, 201610 yr by Wino

There are two sealing surfaces, both anular, sump-to-washer and washer-to-underside of bolt head.

So are you suggesting that oil can creep up to the mating plate of the sump and underside of the washer? Then possibly held in place in that narrow gap between the Bolt/OuterFaceOfWasher/InnerFaceOfWasher?

 

Maybe I should inspect a sump bolt for oil at this gap by undoing it a little. Its a bit too risky for my liking.

 

EDIT: Are the sump bolts all stretch bolts? in which case they would deform after being used once.

Edited 18 May, 201610 yr by UdayP

So are you suggesting that oil can creep up to the mating plate of the sump and underside of the washer? Then possibly held in place in that narrow gap between the Bolt/OuterFaceOfWasher/InnerFaceOfWasher?

 

Maybe I should inspect a sump bolt for oil at this gap buy undoing it a little. Its a bit too risky for my liking.

Yes. It cannot get past the seal between the sump side of the washer and the sump. It can get up inside the washer ID/bolt OD gap, but then that can't get past the bolt head side of the washer - to - bolt head underside seal.

EDIT: Are the sump bolts all stretch bolts? in which case they would deform after being used once.

No. They are not stretch bolts. Torqued to 30Nm. The concern is the captive washer distorts with part of it inside the drain hole and the rest against the sump face, it develops a ridge, which I suppose could give problems if reused and the ridge is offset. In practice, with reasonable care, the plug can be reused a number of times, I suggest 3 maybe 4. Visual inspection of the washer is the key.

Interesting read this. I wonder if the OP is any closer to resolving the low oil level light  issue? Doesn't seem to have been on for a while on this thread.

 

Oil seems an area of many opinions. I must confess, until recently, I have always asked for long life oil even though I change the oil 12 months and usually <7k miles. I found it was the easiest way to guarantee a top quality oil and I had previously done this with all the VAG cars I've owned.  Without that instruction it always seemed a real risk as to what oil the garage would actually pour in the filler.

 

Now having bought the vRS and off loaded the golf, I  read about some of the issues on valve and intake carbon and gunk build up and reading a bit more about oils and also looking at the oil temp in my car which even in 14C ambient, at motorway speed sits at 100C,  I'm thinking the fixed interval rated stuff that is usually 5w40 would offer better protection under load and given the relative modest mileage. And possibly reduce valve contamination by not being so thin.

 

I'm going to use quantum platinum next time perhaps at the expense of a little fuel economy, I think the viscocity at the higher temps can only be a good thing as long as I don't leave it past 10k / 12 months.  My vRS is 5 years so will probably do all the routine servicing myself now anyway so much more control that way.

 

Edit. plus without all the extra additives, fixed oil is a lot cheaper so it has another advantage but that's not why I am changing.

Edited 3 June, 201610 yr by TheClient