Originally Posted by Diesel911

I did the soak on my Volvo. I had not relized until Summer came I had been driving with a Thermostat that was opening too soon and engine temp as too cold. The result was I had light Gray Smoke most of the time.

I was skeptical about it working but the Marel M Oil worked. I just removed the Glow Plugs, used a Funnel with a Hose on it and dumped in about 1/4 cup. Let it sit 5 days; rotated the Engine and soaked it again for 3 Days.
Change the Oil and tool it for a hard Drive on the Freeway.
Remember it will only work if you have Stuck Rings due to A Carbon Build up or something that the Marel M Oil can work on.
But it worked for me.

Below is what I have in my notes.
Marvel MM oil results sticky rings
Origional thread also has + response
http://www.peachparts.com/shopforum/showthread.php?t=258757&highlight=Marvel
Well it loosened the carbon as the compression has increased in the two low cylinders! # 3 was 320 is now 380 and #5 was 160 and is now 340! Drove it about 20 miles hard and fast, there was some carbon coming out the exhaust! Will be taking iton two longer trips this next week: Monday I'll be going over to the coast (SLO) and the SoCa gtg on next Saturday. The trip over the Grapevine should help!
Email response about if it reduced blow-by
The blow by was reduced and also with the nice drive to San Luis Obispo my rpms are lower than they were before! Before 65@3,250 now 2,850, before 70@3,500 now 3,150? and boy does it have power... but the glow plug light is now out (starts ok but the weather is warm. The relay works, so I'll be checking the plugs) and the fuel gauge is dancing (ground?). Oh, well gives me something to do...