Thinking about buying a 2003 s40 with about 110K as my fist Volvo...
Any tips on what to look for before purchasing ?

 

common problem areas:

1) broken springs. Look at all four corners - usually the springs break about 2-3 inches from the end so you may not notice it right away
2) VVT gear/solenoid issues. Look for any oil leaks around the front cam seals / timing belt.
3) Timing belt age. Should be done on or before the 10 year/100K mile interval. Look for a repair history or markings on the engine. If its never been done, plan on a "major" asap including water pump, idlers, tensioners, serpentine belt, timing belt.
4) rear brakes. A pain for DIY as they have the screw in calipers (to compress you press/turn).
5) flex pipe. The turbo to cat downpipe has a flex pipe that can leak.

As with any used car purchase, check Carfax and any other available repair history. Make sure all components work (does the AC blow cold? stay cold for 10-15 minutes or more? Does the heater work - no smells? )
Is the car clean? (any gunk visible from the oil fill? (stains are normal) is the transmission fluid red or dark/smell burnt? is the coolant green or brown? Generally my view is if somebody doesn't keep the car clean, can you expect them to keep book maintenance?
Make sure there's no check engine light or ABS light etc.

 

Very similar thread here, should give you what you need...

https://volvoforums.com/forum/volvo-...vo-okay-86035/