I've been reading the Haynes manual for my new '85 740T. I mentions checking and adjusting the valve clearance every 24,000 miles. Is this for real? Just about every modern car has a non-adjustable hydraulic valve-train. Well, the manual also mentions using shims to set the clearance??? Older cars I've had allow you to turn a screw and locknut to adjust the valves (both with overhead cams and push-rods). Any tips on where to locate replacement shims? There is no Volvo dealer even remotely close to where I live. Do they come in an assorted package or do you special order them by size?

Any info is helpful.

Thanks to all who helped with my "engine bogging down" problem. Turned out to be a 25 cent piece of fuel hose in the gas tank that failed, thus starving the engine.