I've had three 850's so far.
A Diesel. Had it chiptuned. Aftermarket ECC had to be replaced. Cost me USD 2.000. Ran it for about 2 years.
A 10 Valve gasoline car, converted to run on Liquefied Petrol Gas. (Any idea how cheap that is...) Sold it when it had 453000 km (300.000 miles) on it. Replaced cylinder head (cost me about USD 1.000)
My current one: A T5R Turbocharged station. When I just got it, it ran badly (smoking, stuttering at higher RPM). I knew this from the test drive. But since I know how well the engine is designed, I trusted it was no problem in the core of the engine (head, cylinders, pistons, turbo), but more likely bad maintenance that could be improved.
Turned out it hadn't been serviced for 2 years (haunted down last owner, he told me). They put wrong plugs in: imitation, wrong type and the were worn out). They put imitation cables and rotater in. These engines are very sensitive to misuse in that department. We put in the right stuff and problems solved. Yes, a complete overhaul, (as advised to me by mechanics less familiar with Volvo) would have solved the problem too, because then new plugs 'd have been put in as well. But complete overkill. Next week I'll have an LPG installation put in again (car is now at 225.000 km = 150.000 miles.
In general: These cars are very well designed but have small tolerances. For instance, the engine is made out of aluminium instead of steel. Much lighter, but much more perceptive to heat damage as well. You cannot just throw in some parts or lubricants that seem just about right, (like in some X year old American car with a huge gas guzzling engine in it based on engine technique dating back to the 60s, repairable with hammer and a spanner (yes, I am exaggerating) ), you need to use high end stuff of the correct specs.
Reading the posts here, I see a lot of examples of overkill repairs, and things that seem to happen when people who do not know EXACTLY what they're doing, do standard maintenance and problem solving using wrong parts and fluids, and who don't know the peculiarities of these cars.
Here in Europe, on the roads you can see many ancient Volvos and Mercedes. No other brands have that many that old cars on the streets. That says something about quality. But yes, they do have some typical faults. Not expensive to deal with if you know your stuff. Expensive repairs can happen though, but are usually worth it because these cars keep on running. They are sold here for fairly high prices with 600.000 km (that's about 400.000 miles) on them.
Would you buy another car from this manufacturer? Yes
Review Date: 20th February, 2010