I have a 93 300sd with 215,000 miles on it and it has oil consumption issues.I have been told by several people on here that this particular engine is referred to as a rod bender. While I have no doubts about that I wonder if the MMO soak would be worth a try,have not checked the compression but do not have any hard starting issues either.It does idle a little rough though but runs smoothly under a load or at cruising speeds.

It might help if you believe you have stuck rings due to carbon or other build up.
Remember we are speaking of pouring it into the cylinder. No one is recommending putting it in the Crankcas Oil.

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84 300D, 82 Volvo 244Gl Diesel