I am always skeptical of any magic potions or home remedies to cure car and bike ills, but i will admit to utilizing such witchcraft on occasion and moreover on more than one case these additives have proved themselves worth the cost or effort.
So here are a few cases of me using additives (Or
home remedies) to good effect over the years.
1975 i was 17 just passed my bike test and although i had a few bikes i was buying and selling trading up to greater things, and needed one to run daily to keep getting to work etc.
Bikes were scarce at that time and, nothing about localy my triumph 3TA was in bits frame off build and i sold a suzuki T350J on thursday night and took a 1972 Honda CD175 in PX for the suzuki sight unseen to be dropped off friday wile i was at work.
My Dad drove me into work with the parting shot at the gates at 6AM " Get your self a car or bike sorted out i am not doing this, do you understand." ?
I scrounged a lift home with a chap from work, and rushed in the house asking my grandfather if a bike had been dropped off. It had. Great.
Well not so great Looked good bright red and chrome tank panels good chrome paintwork clean etc. Key in Ign lights on choke kick and it struck up. quiet went in to gear clutch fine ... But Smoke. ... Wow! i mean smoke blue haze and give it beans it probably smoked as much as the T 350j did and that was a two stroke.
Well I was in trouble needed that bike, i ran it and it got no better. oil change breather etc ... no still smoking.
Local garage used to have the old redex dispenser pump stood next to the pump, free to customers put a squirt in the fuel etc.
I was going out with the Lass who worked there at that time and i got a couple of pints of redex and threw it through an oil can straight down the carb . It was barely running wide open throttle puvering smoke out just kept feeding it in so it would just about keep running t was struggling to breath at the finnish but eventuly i ran out of redex and i jumped on and rode off up the lane with a huge smoke trail.

It cleared and to my utter amasement stopped using oil from that moment on. Must have freed off some stuck rings or other at a guess, ran it 6 months perfect sold it no come backs. .
Redex
Fast forward to 1990s I bought a daihatsu fourtrak / rocky 2.8 turbo diesel. was filthy dirty i pressure washed the car and the radiator was made up with hard limestone mud. i had to spray it a wile , and sure enough the jet must have found a weak rusty sector of the rads core.
Green coolant running out like a tap, quick!
Half a dozen egg whites latter and the leak stopped and that car went on to cover 50K miles over the next 6 years and never used or leaked a drop of water.
EGG White. ( Home remedy. )
fast forward to just last month, and my daily driver vauxhall astra 1.7 cdti, had been on motorway several hours from Lincoln , got off A1 near richmond N yorkshire. cr at idle went lumpy running and knocking like crazy. I cleared the roundabout and could see nothing obvious,
Oil ok etc, so i guessed a stuck injector or rail pressure issue. Though maybe a new injector loom or possible injector swap might cure it no code reader, so got picked up and dropped back at the farm with the Rac AND DECIDED TO TRY SOME WYNS DIESEL INJECTOR CLEANER.
Just poured it in the tank and started car ticking over and throttling it just enough to stop it stuttering and knocking. Literaly within 10 mins it was ticking over super smooth.
it worked great . Just changed the oil in case of any diesel wash ingress and repeat the aditive in the tank next two fill ups, here we are 4k miles latter running perfect.
Additive can in some case work well.
Wynns diesel injector cleaner.