REDEX REVELATIONS
You asked if anyone still uses Redex. Well I happen to use it on my cars, but I do question whether it is truly effective. It is marketed as a fuel system cleaner, and I suppose the primary ingredient of Redex, Naphtha, potentially can do this. I do wonder however, whether 250ml (the recommended dose) dissolved in a full tank of fuel, say 50 litres, will actually be useful (0.5% concentration).
I’m guessing that the constant, low concentration of naphtha gradually erodes any fuel system build-up of contaminants. Hopefully such components as injectors, fuel lines, etc will be kept clear and clean. Once naphtha is combusted, it seems unlikely that it can clean the EGR, or sensors, or cat. What’s more there’s no claim by Redex that it can, so the story really stops there.
Cataclean on the other hand claims to be able to do anything Redex can, AND clean components post-combustion. The main ingredients are acetone, isopropanol and xylene, all of which are potent solvents. When a bottle (450ml) is dissolved in approx 15 litres of fuel the concentration is around 3.5%, which is much greater than Redex. I can appreciate that this could dissolve deposits in the fuel system much better than Redex assuming equal efficacy between naphtha, compared with acetone, isopropanol, and xylene.
So this leaves me with a quandary. Is Redex actually a waste of money, and should I use Cataclean instead? Or should I use both? I don’t know. What would be particularly useful would be an actual real world test on a dirty engine; to actually dismantle it to see the state of components such as injectors, EGR valve, exhaust sensors, etc before using Redex. Then regularly use Redex for a few months, dismantle and see if the components are clean or not. Same for Cataclean. This removes the anecdotal and leaves us with true facts. Now, that would make for an interesting test. Mr D Forbes
Referring to the use of Redex, I have been using it for years as an additive to my petrol and think it’s a great upper cylinder lubricant that is beneficial to the engines of my previous vehicles. My current car is a Skoda Octavia 1.2, which seems to be very smooth with regular doses of Redex.
Bill Mclean In the April 2020 edition of Car Mechanics you asked about present or past use of
Redex. In the late 1970s I ran a Triumph Vitesse Mk2 2-litre convertible with overdrive that had been upgraded with alloy wheels, six-branch exhaust manifold, Recaro seats, etc.
It also had a ‘Redex lubrocharger’ fitted. This was a device on the dashboard that was connected to a can/tank of Redex that was positioned behind the trim to the right of the driver’s footwell. The gauge/controller on the dash was also connected via tubes to two drillings in the inlet manifolds (twin SU carbs rather than Strombergs). It was possible to fill the gauge with Redex (turn the knob and press the button, if I remember rightly) and then inject it direct into the engine as you drove along. I had not seen such a system before or since.
I used Redex in cars I owned after that, including putting it down the plug holes and leaving overnight and seeing lots of sweet-smelling smoke at the beginning of my next drive.
I just want to add that I enjoy reading CM and find it very informative. As a retired teacher/lecturer I must praise you all for the excellent written English, which appears quite rare in motoring and many other publications these days.
Peter Rolfs
In the late 1970s I used Redex in my Vauxhall Viva to combat carbon build-up – in the plug holes, down the carburettor, in the fuel tank. I found it very good. Later I had a Mk1 Cavalier – it suffered bad from pinking, until I used Redex regularly in the fuel. After a couple of fill-ups the pinking stopped – as long as I used Redex the pinking never returned.
Up to modern times, I had a 2005 Audi A6 2.0 TDI and one day the emissions light came on the dashboard – I thought, Redex! After a couple of fill-ups, the light went out.
Now I have a 2009 Audi A6 2.0 TDI and use Redex at every fill-up – excellent product.
Mark Blundell