Mercedes Benz repair: 1982 mercedes 300d with little power, mercedes 1982, diesel mercedes

Question
my diesel mercedes 1982 300D have little power when going uphill (i am not talking about steep hills but very very small ones). sometimes the car does not go more than 20 mph. also sometimes it goes no more than 35-40 mph on plain terrain even with all the gas pedal down.
i undestand it is an old car (240,000 miles) and i do not expect it to run 90 miles per hour uphill but certainly 15-20 mph is too little, specially when you are on the highway and everybody is screaming at you thinking you do it on purpose.
any suggestion will be appreciated.
thank you very much
Pepe from Costa Mesa California


Answer
These engines have very little power to begin with and the culprit in this case is usually compression. You probably need to have a valve job done at a minimum and most likely a total overhaul. Have the compression checked that will tell you what you need to do. Good Luck!