This website contains age-restricted materials including nudity and explicit depictions of sexual activity.
By entering, you affirm that you are at least 18 years of age or the age of majority in the jurisdiction you are accessing the website from and you consent to viewing sexually explicit content.
Bleach, in the radiator mythbusters did this one, sugar won’t even slow down a modern engine, water is kind of shitty but you can just drain it and restart. Bleach in the radiator will age the engine by a decade for every 10 minutes its running.
Can’t find that one – did you mean bleach in the oil tank?
https://mythresults.com/episode15
That might be it!