Hello all. Trying to change my oil after needih to top up wih mixed oil after a leak. Sump nut is spinning in place, neither tightening nor loosening.

How do I get the thing off and how likely is it that my sump is knackered?

ASV engine, 2003 if it makes any odds

ASV engine, 2003 if it makes any odds.

if the sump pan is pressed steel it probably has a threaded boss for the sump plug, so I would suspect that the boss is spinning in the sump. can you see what is rotating.

It will be aluminium on the ASV. You could lever it out whilst turning but it will need either a helicoil or a new sump. Personally I'd go with a new sump and bolt.

Can't see what is rotating, no.

Also, what is a helicoil?

Helicoil is a replacement thread insert which is fitted after the original thread is removed. Unless you know a cheap engineering shop, I would go with the new sump option, as it is not too bad a job if you take your time, and they are not as dear as they once were in places like ECP and other online parts shops now.

An engineering shop put a helicoil in for me 10 years ago, it was 50 quid

You will need to use a screwdriver to pry it out whilst turning as per Tech1e.

 

And seen as you have to remove the sump anyway to get it repaired I would just fit a new sump and sump plug. 

 

And remember to be gentle with the new one

An engineering shop put a helicoil in for me 10 years ago, it was 50 quid

I put a brand new sump on the Croctavia and it was less than that plus a little bit of gasket sealant stuff. You know it's right then plus you can inspect the pickup and get rid of any contaminants at the same time.

OP, just get a new sump.

I'm new to the site,but had the same problem on my Octavia ally sump. After getting the plug out ,I bought a 16mm thread sump plug and washer which I think was Peugeot ,and a suitable 16mm tap from fleabay .As the old thread was torn out the new tap cut a new thread no problem. Cheaper solution and a lot less hassle!

I'm new to the site,but had the same problem on my Octavia ally sump. After getting the plug out ,I bought a 16mm thread sump plug and washer which I think was Peugeot ,and a suitable 16mm tap from fleabay .As the old thread was torn out the new tap cut a new thread no problem. Cheaper solution and a lot less hassle!

If you did that with the sump in situ wouldn't there be a risk of bits of metal getting into the sump?

 

Personally I'd fit a new sump (or good second hand one).

Agreed a small amount of swarf may get in the sump but no more than a helicoil done in situ.Realistically the sump strainer and oil filter will remove the bits and protect the engine.

Agreed a small amount of swarf may get in the sump but no more than a helicoil done in situ.Realistically the sump strainer and oil filter will remove the bits and protect the engine.

 A fresh gallon of oil through the engine would probably help flushing bits out as well but personally I wouldn't even think twice about it, I wouldn't be able to sleep at night knowing there may be bits of swarf floating around

Obviously you need to have peace of mind with whatever you decide. My Octavia still running like a swiss watch 5000 m after repair,mileage now 177000! 

Replace the sump, and the oil pick up pipe at the same time. Helicoiling or anything else is more bother than its worth.

Wurth make a thread repair system which is called the 'Time sert' unlike the helicon which is only recommended for a single use the Wurth time sert is a permanent thread repair.

Minimal swarf would be left in the sump if really worried put a blob of grease in to catch any and suck it out after.

https://eshop.wurth.co.uk/Thread-repair-set-TIME-SERT-THRREP-KIT-COMPL-M5-M6-M8-M10-M12/09649617.sku/en/GB/GBP/

Wurth make a thread repair system which is called the 'Time sert' unlike the helicoil which is only recommended for a single use the Wurth time sert is a permanent thread repair.

Minimal swarf would be left in the sump if really worried put a blob of grease in to catch any and suck it out after.

https://eshop.wurth.co.uk/Thread-repair-set-TIME-SERT-THRREP-KIT-COMPL-M5-M6-M8-M10-M12/09649617.sku/en/GB/GBP/