Engine Oil!

I used to use my mums "mazola" in the cooling system in 1976 in my green vauxhall viva to stop it boiling over! And castrol R40 in the sump because I liked the smell...

I read it again...

Yes you can use pure castor oil but its not multigrade (glue when cold and thin when hot! And this will have at LEAST as higher film strength and as good a anti wear properties as ordinary mineral/synthetic motor oil. Provided you warm up the oil in winter somhow and change it very often! It has no detergent or anything to keep corrosive acids at bay! Although these could be added.

You could do the same with corn oil (from smashed corns???) or many other crop oils. Baby oil might be good! (Made from squashed babies) available from boots chemists. I used to add this stuff to model aircraft fuel.

You could with some reservation use gear oils, transmission fluid, hydralic oils, etc etc. The difference is that they are not multigrades (or not multigrade enough) so would need careful warming up and a watch on the high temps!

And they dont have the right additives for dispersing carbon, keeping it in suspension, or the right anti corrosion and acid neutralising components. But if you change the oil every week it wouldnt matter a lot!

I do have to ask why you want to know this though???

And... I presume you could drive carefully with a sump full of powdered graphite!

And you COULD design a motor that needs no oil. (sealed ball bearing races packed with grease) on all bearing/crank surfaces, high temp self lubing plastics for liners etc...

Or a turbine that uses sealed bearings???

I vaguely recall some Japanese experimental ceramic engines were claimed to need no oil at all. However ceramic engine components have been expensive and their use by the military (cost no object) has been rare, let alone in mainstream engine manufacture. Best we get is "Nikasil".

that last quoted word is still a swear word thank you very much :)

At least you don't have some Alfa-loving chap saying, "I told you so" after every comment, eh?