This thread is so old but I thought I'd comment anyway. Check out my video here: https://www.youtube.com/watch?v=0HcOwWHtxTA I bought this new tank online and it was a Volvo genuine coolant tank. After 10 days it went bad. I did this test where I compared it to a new tank and I realized the tanks fl...

Instrument panel (DIM) might be a cold solder joint on one of the chips, some areas go wonky (clock as another example) and the issue progressively gets worse until the entire DIM goes blank (experienced this on a '03 S80). That your information windows is not working may be a symptom of a pending f...

For testing fuel/air ratios, it's easy enough to see the performance in VIDA (software that interfaces with the vehicle via a DICE unit) if you have access. Might be some other readers that can pull metrics as well, VIDA is all I know. If I were to "guess" at the rear O2 sensor problem, I ...