x2 on the Valve Adjustment. Run it a while after the adjustment and retake the Compression on that Cylinder to see if it goes up.

What does Marvel M Oil do to multiviscosity type Oils concerning their ability to be multiviscosity?

If He wants to free some stuff up some members have said that using Synthetic Oil will do the trick.

He could soak the #1 Cylinder in Maver M Oil; that way there would only be about 1/4 cup to to dilute the crankcase Oil.

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84 300D, 82 Volvo 244Gl Diesel