Rather than add to existing posts, I thought I'd do a separate one for the mk3 V70 timing belt as I've got a few useful points to add.
I replaced the timing belt, timing belt tensioner & idler, auxiliary belt & tensioner, and also the air-con compressor belt.
I'll try not to repeat what's already been said in the existing posts, but they should also be read if you're attempting this:
http://www.volvoforums.org.uk/showthread.php?t=189294 (aux belt change - on page 3, I've added a couple of links to some very useful YouTube videos)
http://www.volvoforums.org.uk/showthread.php?t=252457 (timing belt change)
It's worth me highlighting how useful SiRobb's YouTube videos are (as referenced above). They're very well explained by someone that clearly knows good mechanical practise
Overall, everything I did is achievable by one person in a day (well, I managed it, so I assume others can too).
This sounds obvious, but make sure you have the right tools. I'd assumed my torque wrench was big enough, but it was only a 220Nm max model. Luckily Halfords do a 300Nm in their 'Professional' range, for £90 and it's quite decent (no-one else in Manchester had anything in stock this big, so good-on Halfords for stocking such items). I'm very glad I bought a crankshaft pulley holding tool, and I was damn lucky to find one in stock locally. Machine Mart had one left in the UK, and it happened to be in their Manchester branch. And you'll need some really small ratchet/sockets, i.e. 1/4" drive, in addition to the big stuff.
And while I'm praising suppliers, I should mention that eBay seller 'volvopartstrade' was helpful and shipped everything next day (all sealed, genuine Volvo parts).
As always with car mechanics, there's always something that isn't mentioned in the Haynes manual that catches you out and adds hours to the job. Main observations:
Timing belt cover.
Front timing belt cover removal and replacement is a real pain due to very long threaded stud used to mount the coolant hose bracket. I had to use a long screwdriver to lever the inside of the cover outwards. As there's almost no clearance, it's very difficult to lever the cover, especially with the added risk of slipping and hitting the timing belt with the tool you're using to lever the cover open. On refitting, this meant it was impossible to align the bottom lip of the front cover so that it fitted inside the rear timing cover. After I finally managed to seat the cover over this threaded stud, I then had to bend the outer timing belt cover lower section and lever the front cover with a screwdriver - not easy when there's no space. After all that bending of the cover, it now doesn't sit entirely flat, so will allow a bit more dust into the timing belt region than normal. If I ever need to remove this front cover again, I plan to cut about 10mm of this threaded stud as it's much longer than necessary.
Engine mounts.
Compared to the mk2 V70, one slight annoyance with the mk3 V70 is that you have to remove the top drive-side engine mounts before you can remove the timing belt front cover. You have to do this twice* (see further below).
Haynes manual was no use at all for this. Luckily the Dayco video I posted recently shows exactly how to do this. It wasn't hard to remove and refit the mounts. You just need to be patient getting the bolts back in while setting the engine height just right using a trolley jack supporting the engine.
After fitting the new belts, tensioners and rollers, it's necessary to run the engine for a few minutes to make sure all the belts are running perfectly true. *Before starting the engine to carry out this observation, it's necessary to refit the engine mounts. Obviously you then need to remove them again to fit the timing belt cover.
Timing belt tensioner.
After I ran the engine for a few minutes after fitting all the new parts, the timing belt tensioner indicator had moved about 10 degrees to the left. It hadn't slipped. I'm going to assume it's just the belt's teeth 'bedding in'. Obviously it was easy to reset the tensioner, but I'm not sure whether I can expect things to bed in further, and whether I should therefore inspect the tensioner indicator (as above, I'm not keen to go through all the faff of removing the timing belt cover/removing engine mounts to inspect this).
Torquing up bolts.
The Haynes manual provides the required torque settings for the tensioner and roller bolts. However, in typical Haynes fashion, it doesn't tell you there's no chance of fitting a torque wrench into the narrow space between chassis and engine. So in my case, I had to 'guess' the torque using my narrower 1/4" and 3/8" drive ratchets.
Regarding the crankshaft pulley nut, my 'claimed' 650Nm impact wrench took about 4 seconds to turn the nut. After about 3 seconds, I was starting to worry, but all was good.
When it came to tightening up, I'd never used my torque wrench on max before (300Nm) and was worried I'd break something before hearing it 'click'. It really did need all my weight on the end of the wrench, which of course isn't quite possible as you can only position the wrench around the 4 o'clock position, inside the wheel arch.
Crankshaft pulley holding tool.
After experiencing just how tight 300Nm is, it became apparent how essential this pulley holding tool is to hold the crankshaft pulley still (you'd really not want all that torque going through the timing belt !). I've seen pictures of it holding itself in place against the chassis, but on the mk3 V70, there isn't any structural member lying perpendicular enough to safely use this tool. Fortunately, if it's positioned around the 8 o'clock position, it's just long enough to hit the underneath of the driveshaft (see photo).
Other essential tools.
Due to very narrow clearance between timing belt tensioner and chassis, I had to modify a 6mm hex key to fit into the tensioner (see photos of tools).
This narrow clearance also meant only a small 1/4" ratchet and sockets could be used to tighten the timing belt tensioner main bolt, and I think also the timing belt idler.
When first checking that the new belts are in place, and to check alignment of crankshaft/cam pulley timing marks, it's necessary to manually turn the engine a number of times. I needed to use a couple of 300mm 1/2" extension bars with the 30mm socket and ratchet, otherwise it wasn't possible to view the camshaft pulley turning at the same time as you're cranking the engine.
Parts used:
I wasn't able to find genuine volvo bolt kits, so had to use the existing crankshaft pulley nut, bolts and the bolts for the timing belt tensioner and idler. The auxiliary tensioner (31330379) came with a new T40 bolt.