hello,

i have low compression on my 1982 240D with 250K miles

how do you tell which is the problem, valves or rings.

any suggestions would be appreciated

brian

 

Put about a teaspoon of oil into each cylinder (one at-a-time), and measure the compression again. If now, it significantly increased, than its your piston rings. If no change, than most likely its your valves, or a valve adjustment is required.

Phil