The 2007 V50 needs a bit of coolant and to me it looks blue. What's up with blue coolant.

I do have some around for the S60, it is G-05. Can I use that in the V50?

Early spring I was too lazy to replace the top motor mount and took it to a shop. I am thinking that they may have lost some out of the reservoir when they moved it out of the way.

I'm also thinking they spilled some on the serpentine belt and pulleys. From the day I picked it up from them the pulley or belt has been making a noise.

If you are just 'topping' it off, the G06 won't hurt.

It is good sticky stuff, try wiping the S belt with a damp cloth and see if that makes a difference.
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Keeping it running is better than buying new

I do not know about your car in particular, but a few years ago I read a couple of articles in Commercial Car Journal and they said that your cooling system can be destroyed by mixing the wrong coolants.

As for the serpentine belt, new synthetic belts do not crack, they wear out like tires do. Gates belts has a free gauge you can get through their web site.

After 100K miles, a belt is worn out and can slip.

I beg to differ, timing belts are toothed and cannot 'slip'. They can break with age, and they do develop visible cracks with age. Newer Volvos, 1999 and younger, have a tensioner that is the weak link. If the tensioner fails, it is possible that the belt will either fall off or 'slip'.

Serpentine belts, running the alternator, AC, PS, is not toothed but ribbed. There is a gates tool to measure the depth of the ribs, but if the S belt is changed when the timing belt is changed, it should be just fine. The S belt might slip, and when it does, the driver will hear the noise quite well!

Antifreeze spilled on a belt is not good news, but it can be washed off with copious amounts of water. The problem is then, the ribbed or toothed side of the belt and the gears and rollers that are turned with the belt. It is quite difficult to clean with the car jacked up and the engine running.

I had an alternator fail due to antifreeze being spilled on it. The antifreeze got into the copper coils and really messed things up.

With all of the autoparts stores selling timing belt kits, I wonder why they don't include the serpentine belt???
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Keeping it running is better than buying new

I'm old school about belts and pulleys. I just remember something about belts / pulleys don't like getting coolant on them. I can't say that is what the mechanic did but because you have to move the reservoir out of the way....he could have spilled coolant.

So you can't look for cracks to determine health on the new serpentine belts. Good to know.