As above, need to watch the cooling pipe from the transmission, early models also had the wiring loom hooked at the bottom of the fan assy. At some point Volvo went with a tricky larger connector the the fan assy A fresh video with alternator and cooling fan removal tips .https://youtu.be/zlp6qvYBJMU

I had vibrations from cv joints, but it was constant above 50mph speeds - basically exactly like an unbalanced wheel however with the difference the vibration would differ in intensity depending on the road surface sideways angle - somehow different on the left vs right line. I also had at a differe...

Good update. Don't forget to test the battery with the new alternator, faulty alternators damage batteries and the vice-versa is equally true

100K miles is a bit early for the flexible downpipe to leak. The other place is at the flange between the catalytic c and the first muffler. It's actually the flange on the cat side that wears at the bottom and starts leaking - so the gasket no longer seals. Only way is to grind to resurface the fla...

Didn't read all, but maybe the fuel pump is about to fail ? Also thinking about the ETM on these early XC70 As for the evap code, maybe check this valve - I believe on 2001 it's located on the radiator fan www.youtube.com/watch?v=0H2lIuQ8e34

I'm thinking at the glove box, when flipped open, there's 4 of these that secure the outer inlay, or maybe one of those that secure the glove box to the dash - there's several of them

Seepage is common at the rubber hoses both at the reservoir and pump. The hose does wear inside - or the clamp gets slack, the fastest it to lift&empty it, chop 1in off the hose end, put back. Did so and no more leaks - also use the Volvo worm clamps with round holes. Your 03 tank also has outgo...

Well, test the battery by undoing the negative, leave 1h, see how much V
But yours being a 2003, more likely faulty DIM - search forums, Ebay repair service $150 battery HAS to be disconnected while removing it

If the belt is moving left-right on the cam pulleys, it's a problem with the tensioner. I'm not saying it's really bad, but worth replacing it. My belt was also 'walking', after replacing the tensioner is now steady. Also, the belt should be sitting about centered on the cam pulleys, not near the ed...

There are several other things to check before suspecting the catalytic converter. See the heat shield right above the exhaust manifold - behind the engine, it breaks at the securing bolts and starts rattling. The rest of the exhaust also has several aluminum heat shields that break at the securing ...