Try to remove the Marvel oil.
Refill with PB blaster = PB Penetrating Catalyst, you can buy it in gallon cans.

http://www.pbblaster.com/

I just used it on a Bronco 2 that was Locked solid, three weeks of soaking, and it cranked over with a short half inch ratchet.

I filled the cylinders, and dumped the rest into the throttle plate, when I came back three weeks later, all of it was in the oil pan.

__________________
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Noise Vibration and Harshness (NVH).
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Heat exchanger durability.
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1985 300SD
1983 300D
2003 Volvo V70

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