Has anyone ever used Marvel Mystery Oil to free up an engine? I'm working on a 1968 Mack Diesel that seems to be frozen up. The guy thinks it got some water down the cylinders because it had water in the oil and won't turn over. It last ran about a year ago. I'm thinking about pulling the injectors and pouring a few ounces of oil in and letting it sit for a few days. How much is too much? How long should I let it sit?
pour a whole quart in there and let it sit , if it won't unsieze you can undo the rod cap and try to push the piston assy out with the liner , on a Mack your better off replacing the liner when it rusts as it will eventually crack in the area of the rust or cause uneven heating and the liner will be almost imposible to remove without damaging the block .
FWIW. On the land speed racing forum the results of a comparison study of commercial penetrating oils was posted. A concoction of a 50-50 mix of acetone and atf easily outperformed all of them. I brewed up a batch to use on some bolts on my Monza with good results. I don't know if it would work in your application but it might be worth a try.
"Machinist's Workshop magazine actually tested penetrates for break-out torque on rusted nuts. They arranged a subjective test of all the popular penetrates with the control being the torque required to remove the nut from a "scientifically rusted" environment.
The ATF-Acetone mix was a "home brew" mix of 50-50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price."
al_inbancroft wrote:X2 on the 50/50 acetone/atf mix. Acetone has a high absobtion rate that makes it penetrate like a terror. I use this mix all the time. The best Ive found. Good luck Pappy.
That's what I used, dumped some in each cylinder and left it sit for the weekend. I disconnected the drive shaft, put the tranny in high and turned the drive shaft with a pipe wrench and a long pipe. After a few flying leaps it broke loose.