We're currently in a typical chilly spell here in the UK and I've got a bottle of Redex fuel additive sitting in my cupboard, like this one:


I've used it before in my little 2006 Ford Ka 1.3 and it usually perks the engine slightly and seems to give me a longer distance on a full tank.

Is it good or bad for my engine to put this stuff in it during the winter months? Or should I keep hold of the bottle until it warms up a bit?

2 Answers 2


According to Holts, the cold affects your fuel's performance adversely. However, their last line reads:

Of course, the best way to improve your fuel economy is to add a shot of Redex fuel additives to your engine each time you top up the tank. Our products are developed to help your engine work at its optimum, no matter what winter throws your way. To find out more, visit the Redex website.

Which I think means it will help, because adding Redex always improves an engines performance if it is currently working sub-optimally.

So go ahead, knock yourself out! Mind you, if you were to wait for the summer, you might get to go faster as well. Tough call.

  • Would you consider "always improves" to be a rather strong statement? Jan 6, 2017 at 15:12
  • I'm sure that Holts would say that, since they are making money from people using the product. But at least they say that it's fine to use in winter right there on the site. For that reason and the fact that JonMark went out of his way to do a little research, I am marking his answer as the right one. Cheers!
    – bitofagoob
    Jan 6, 2017 at 17:15

Shouldn't matter when you use it.

Essentially, the fuel and additives are relatively unaffected by seasonal temperature changes, barring extreme climates. As such, it won't do anything different in winter than it would in summer.

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