So I'm just curious are head gasket issues a common thing on this generation Volvo's if they're well maintained?

Are transmission issues common? I keep hearing that these Volvo's can go 300K -500K miles without any major issues.

What are some major issues some of you have run into? I'm really just curious, and trying to do as much preventive maintenance.

I'm currently replacing the rear cam seals, dip stick seal, turbo drain pipe seal, and PCV system

 

The only time I have heard of a headgasket failure is if the engine gets overheated. If the vehicle is well maintained, timing belt and all pulleys changed every 7 years or 70,000 miles, oil changed every 5000 miles (with synthetic oil) and the trans fluid changed every 50,000 miles, the car should last for 300K and beyond. Our 95 850 had 280K on it when we sold it and the new owner has already taken it over 300K.