Hi James,
What a calamity. I think you have to fix it though - it will wake you during the night if you don't (even though using an extraction pump may work perfectly well for years).
If the bolt is rounded now, I suppose you can be as aggressive as you like. Hammer on a twist socket as far as it will go then use your breaker bar and a 4' length of fence post. Remember: lefty loosy.
If that doesn't work then weld either a bigger nut on (use an arc welder and fill up the middle of the nut) - the heat from the welding will help loosen the bolt as well. I've done this one myself a few times and it has worked - although generally on bikes where everything is more exposed - and never on a sump plug.
Good fortune,
Alan

I've had the misfortune to need to do it on sump plugs before - can confirm it works :D

good call on re-fitting the under tray, esp when you look @ the right side of the engine and see how close the belts are to the wheel well/road surface, easier for them to have a"oppsie" with flung up debris than the sump !

Well the oil extractor failed to arrive despite it reaching the local DO two miles away by lunchtime and being scheduled for delivery... then cancelled a couple of hours later. Annoying thing is I was actually near the DO so theoretically could have picked it up although not sure it would have been possible if it was waiting for a van. Didn't happen anyhow.

I've put the undertray on for piece of mind though. I can see why they get discarded; it wasn't the best of experiences but will probably seem better next time. Note for the future: fit the centre screw first! I got the other six in then found it was somehow slightly misaligned and the centre one would not go into position.

I also found the threads very stiff to begin with - having been exposed to the elements for who knows how long in the absence of the undertray, they'd acquired some grime and a little rust in some cases. Got the worst off and they were OK once they got moving.

Pre-holiday status then:

- No oil change :( I suppose in the scheme of things doing what will be about 10-12k on the same oil isn't too bad and still better than many cars see, but not what I'm really comfortable with for long-term health based on the colour change observed over the past couple of thousand miles.
- Tank filled, but with E10. I can't really be choosey in the present circumstances and am optimistic we'll find some premium grade once further north. As tomorrow's mostly a motorway day I'll just be happy I've got something to run on, I know that's more than some unfortunate people this week.
- Undertray fitted for the first time in who knows how long. Sump and belts protected on what looks like it could be a very wet day.

The sump plug saga may resume later in the month. A neighbour has offered to lend me a blow torch. I don't know that I trust myself to try that!

Photos of the plug as it is today

https://www.volvoforums.org.uk/attac...1&d=1633114244

https://www.volvoforums.org.uk/attac...1&d=1633114244

(notice how the sump bulges out directly above the plug - there is limited clearance for vice grips or a pipe wrench without scraping it, which I don't want to do)

The head was rounded the first time I got under the car, now it's really rounded and gnarled by vice grips and twist sockets.

Undertray fitted

https://www.volvoforums.org.uk/attac...1&d=1633114244

Looking at that, i'd be seriously tempted to drill it centrally, drain out the oil then use an Ezi-Out to remove it.

https://www.ebay.co.uk/itm/221677188010

Basically a tap with a coarse left hand thread, as you wind them in it starts turning the fastener that's stuck anti-clockwise to remove it.

If you don't fancy that idea, i'd go with the hammer and cold chisel method to tap it round anti-clockwise as viewed. :thumbs_up:

Has worked for me in the past. The hardest bit is getting the stud remover out of the sump plug.

This was a nasty V50 Allen key sump plug, screwed up by the dealer when I bought it and they changed the oil first.

As Dave above says ^^^^^^^

To be honest I was expecting it to look a lot worse than it does. The sump is like new and the plug flange and washer are sitting square and undamaged. I think when it finally comes loose - by whichever method - you will find it will come undone and leave the sump threads undamaged.

options for When you get that out
http://www.stahlbus.com/products/en/oil-drain-valve/
http://www.sumpplug.co.uk/
https://www.ezoilchangevalve.com/volvo.html

still going to Possibly need to remove the under tray to use those
may not be to your liking
Does avoid the whole "sump plug" issue much like the vac extractors

I've used similar on generator engines Andy and in that application they're great, especially with extension hoses pre-fited with the valve at the end near you.

However what's always bothered me for road use is the amount of speed humps and the fact that these valves hang down below the sump.

On my recent MoT i noticed a couple of scuff marks on the fron crossmember of my 760, the sump plug on it is only ~1/2" above the level of the bottom of the crossmember.

If i'd had one of those valves fitted i would have probably ripped it off whenever i scuffed the crossmember! :eek:

i Hear that

stahlbus® oil drain valve

Fits ala , with its dust/dirt cover in place
http://www.stahlbus.com/products/en/...endung_001.jpg

and the extention tube is a "fit to drain" item rather than "fitted to the car"




http://www.stahlbus.com/products/en/...endung_003.jpg

fitting as it does, With a "dirt cover" Should be "speed hump/lovely road surface safe"

https://youtu.be/eaaT5a13xY8[YOUTUBE]https://youtu.be/eaaT5a13xY8[/YOUTUBE]
manuf Video


agree the "tap" shape ones , esp with the "lift to drain" lever May not be the best idea given the "lovely" state of the roads