Twas meant as an upper cylinder cleaner to extend time between decokes. And, wow, how the smoke smelled.I can remember my father "treating" the car with Redex - must have been a Ford Consul in about 1958 - running it immediately after treatment and it emitted clouds and clouds of white smoke. No idea what the treatment did, or why?
I don't think 5p's had even been invented then I guess that must have been down south somewhere, up here in Lancashire it was free at the garage I used.Remember in the old days when petrol was dispensed by attendents? I did the job at an Esso garage, looking after shop and pumping fuel; and if not too busy to give the customer's windscreen a quick wipe and to push "shots" of either Redex or STP, at something like 5p(?) a shot. I think that was probably when a service station was a service station and not a self-service station as it is today
I never used it myself, but I wouldn't dismiss it out of hand. On the oother hand I wouldn't imagine the fact that it produced clouds of exhaust smoke would inspire me to trust it.I think Redex was sold as an “upper cylinder lubricant” the idea I guess being that going in with the fuel it somehow lubricated the valves and rings,,I cannot imagine it really worked though,
I never tried the STP oil additive but I did once try Wynn's, a competitor, with dramatic results. A colleague of a friend of mine had a lovely old XJ6. He got a neighbour to service it for him and after that it made the most horrendous noise. It sounded like someone was inside a cylinder thumping the engine block with a lump hammer. He put the car away in the garage and bought a Rover. I heard about it and bought the XJ6 for cheap. Driving it home was awful, with all pedestrians looking round to see what was making the terrible noise. I didn't know what was wrong with it but on a whim I poured in a can of Wynn's and left the car idling for a couple of hours. Problem fixed, never to return. I can't explain it but I was impressed. And relieved!STP I always thought was an American oil additive,,but maybe they did their own version of redex too?