Old topics on cures for seized engines and Coke

I was looking at an advertized Dexta and the owner said the engine just seized while he was driving it. I went to the YT site and typed in seized engine and there were a lot of old posts concerning this in all tractors.
The interesting thing that is some suggested using Coke poured into the intake or on top of the piston if the head is off.
There are a number of warnings not to do this because of the sugar etc.
If Coke does work there is only one reason why I think it would.
Among the ingredients in a lot of soft drinks is phosphoric acid. If you are going to tear down an engine anyway why not use a very diluted phosphoric acid solution to do this instead of Coke?

Phosphoric acid is used in parkerizing solutions and it will dissolve or convert rust even if diluted, but it will also attack iron and steel base metal if left on. I would think it might be used to free up a seized piston where rust on the rings or rust above or below the piston might seize it, but I don't think it would work for anything else except ruining journals, piston pins, valve guides etc.
Does anyone have any further input on this?

I was originally looking for ways to do a quick field diagnosis to see if a tractor engine is salvageable without having to go farther than draining the oil or pulling the valve cover.

I did not find a specific answer to various causes for engine seizure, but I imagine if I go look at any seized tractor I would drain the oil and look for metal fragments and pull the valve cover and look at things like a dropped valve or a camshaft that is either broken or out of timing due to a broken timing gear or skipped or broken timing chain.
Does anyone else have a suggested quick field diagnosis that a person could do that would take only about an hour to save unnecessary loss of time?

If it seized while he was driving it no magic elixir will free it up. It sounds to me like either a piston or Pistons scored and seized to the cylinder walls or the crankshaft bearing or bearings siezed. Either way a complete tear down is the only way to free this one up. Coke or ATF or PB or all of the rest of them are used to soak a rusted engine that has been sitting too long.

Yeah,

I kind of confused the questions. One was regarding an engine where it seized while running and I was looking for quick ways to diagnose it and other recent fatalities. The other was regarding looking at seized engines where the tractor had sat a while. The Coke question just came up while I was reading posts.

The Coke question was regarding tractors that had sat a while. Not that I would use it. I was just curious.

OK, I mis-interpreted your post. I don't like the idea of pouring anything containing water into an engine except for the cooling system. I've never tried Coke but it sounds like a sugary mess to me too. ATF seems to be the popular piston soaker.

An engine that is properly seized up as a result of setting too long with an uncovered exhaust will respond very poorly, or not at all, to ALL of those concotions.

I had a stuck F20 with aluminum pistons that would not free up with any kind of juice. Soaked it for the good part of a year before I finally had to pound them out. Now it's sitting there apart waiting for me to get ambitious and finish the job.

bought a '52 chev back in the 70's, motor was seized from sitting (we hoped) my dad pulled the plugs poured in some coke, let it sit for a week and I got it freed up, drained new oil fresh tune up and I drove it for a year.
Ever put a nail in a glass of coke? takes a while but the nail goes away, that's why I don't drink the stuff

I have used Coke once to free up a stuck engine. It did remove the surface rust in the cylinder. I think what really got it free was the oak 2x2 and the five pound hammer. I kept the cylinders filled with enough Coke to cover the pistons. I would then whale on it with the hammer and the block of wood. One day I noticed one of the cylinders was empty. From there it was all down hill. Took about 10 days of soaking to get it to start to move. Having said that, I have done the same thing with ATF and Marvel. Took just about as long to get it free.

I bet that you have a spun bearing. More that likely it is a rod bearing and not a easy fix as the crankshaft is going to need work. The entire engine must come apart. Don't bother with that tractor !

While you are googling stuff, check out "knight" type sleeve valve engines. I spent 5 years as the machinst/mechanic for Azeltine, the guy who was THE authority on them. Coke is what we used to get them apart and not damage the 1/8 inch thick cylinder sleeves. That is for engines stuck by rust. One siezed while running is a different animal.

If the engine froze up while running there just aint any magic junk that will free it. Bite the bullet and tear down to see why.

You say it seized while he was using it. Did he just walk away from it and never try to see if it would roll over after it sat a while? I had an engine do the same thing once. Running perfect and suddenly acted like it was being overloaded and died. I hit the starter and all I got was a solid thud. Left it sit for about 20 minutes (this was in the winter)tried it again and it fired right up. Drove it in the shop and let it run for a few minutes. It ran perfect. Tore it down and the #6 cylinder was scored towards the rear of the engine. So, if he never tried it again, who knows? I would check to see if it will now turn over. Not saying this will work for you but, could you imagine the look on his face if you bought it, started it up and drove it on your trailer? No matter if it does or not, I would do a tear down to find out why it happened to prevent more damage. Good Luck!

The tools for the job are a piece of 2x4 and a large hammer. The trouble with seized engines is you can't always turn them over to get at all the rod bolts . If the pistons are stuck to the walls they are getting tossed anyhow.

If I actually do get the chance to check this out I will check the oil first, then pull the valve cover off. If nothing is apparent then I am going to remove the starter and use a special non maring tool to gently feel if the fly wheel will rock back and forth.

I don't want to stress something and make it worse when it might be a seized and scored cylinder. Otherwise I might take a simple repair and turn it into a much more expensive repair like has already happened to me recently.

Actually, I might gently rock it in gear first, but you can feel things a little better if you can get a piece of aluminum rod tapered like a screwdriver and engage the teeth on the flywheel ring gear.

Figure scrap price on non-runners unless uncommon

So that probably being the case. What's the scrap value of a Dexta or a Super dexta with a bum engine? Anybody got a nickel?

I want to thank everyone for posting their thoughts and experience on all the subjects I mentioned. Much appreciated.