You are ruining a good tale with “alleged (R800k)” facts! 
Speaking of. There is another thing that happens on really old cars. The rubber hose that runs that last 400mm to the front brake cylinders can lose its ability to withstand the pressure, and by giving a little, it causes the pedal to feel soft. Replacing those hoses is also a necessary step when you’re hunting the cause of a soft pedal.
Jup … and thanks. The more info the better.
Titbit:
When I used 100% biodiesel, was told to replace the diesel filter “sommer baie vinnig”, and again, and again AND keep a spare in the car.
Holy moly, the gunk that came out!
But that was not all … learned at the time that 100% biodiesel does not work with old-tech fuel lines. The rubber disintegrates. So what, it was time to replace them in any event after wot, 18 years or some such.
The stuff in vegetable oil is indeed very bad for the fuel system, which is why you are supposed to start the car on clean Diesel, move it over to vegetable oil/biodiesel when you have some heat in the engine, and switch it back to Diesel about 10km or so before you turn it off so that the fuel system is filled with clean Diesel when the car is sitting. At least that is what I heard.
With all my research at the time, I never ever heard that.
What are some facts:
- You must have the right fuel pipes etc. New pipes don’t have that problem. Just the old ones. I call it maintenance.
- Your fuel tank, actually the entire system WILL get a “deep clean”. Hence the need for a few new diesel filters when you start off. It is impressive how dirty a fuel system gets.
- Never EVER park the car outside in freezing temps like say in Sutherland in an ice-cold freezing winter storm after rain the evening. 100% biodiesel may become a gel making for a rather interesting repair job.
- Not all diesel cars can drive on 100% biodiesel. Especially the new tech types of diesel engines. They may be able to drive on a mixture of 10% or less biodiesel mixed with diesel. Check with your manufacturer.
- Your BMV EV cannot drive on biodiesel … nope, it cannot.
Titbit:
On all cars, diesel too, over time there is water in the fuel tank. Rests at the bottom.
Wurt Diesel/Injector cure removes that via the injectors.
Cleans out the entire system quite neatly.
Huge improvement ito power and also a resultant improvement in diesel consumption.
If memory serves, I read it in the CAR magazine. Might have been in the letters column. It also had to do with the fact (as you yourself experienced) that vegetable oil gets thick at lower temperatures rather a lot faster, so it was recommended that you “clear the lines” before parking the vehicle. There are chemical stuff in biodiesel that is corrosive to steel and (especially!) on copper compounds. Copper lines were common on older Diesel engines.
Modern engines also require really really clean Diesel for those ultra-high pressure injection systems. The small bits of fish and chips that remains in your carefully strained biodiesel is no good for those systems. And an injector/pump job will completely obliterate any savings on fuel.
Oh it can! I need some extra equipment, but technically an electric car can drive on anything that can be converted to Electricity… which is just about anything, even wood and steam. Conversely the fuel burners are somewhat limited. Petrol cars can run on some types of gasses (LPG for example), and with some conversion work maybe on hydrogen. You also can spend a lot of energy turning electricity into a hydrocarbon to run an ICEV on electricity… it is doable… but absolutely terrible efficiency-wise compared to runnin an EV on just about anything.