Can anyone advise me as to what is the best fuel additive to use in a Focus 2008 1.8 TDCI Zetec model. I want it to perform a bit of an internal clean. Further, is it safe to use diesel additive? Any advice appreciated.

Good quality fuel is better than any fuel additive. A few bottles of redex in the tank doesn't make up for a lifetime of using supermarket fuel every fill up.

Some people claim they have performance gains after using additives but imo it's just a placebo effect. Change the fuel filter, but other than that if it's not broken, don't fix it.

Auto Express recently had this article:

https://www.autoexpress.co.uk/car-news/33200/fuel-additives-are-waste-money

I used to use Millers for years, having been recommended. Don't know if it ever made any difference though, never did a comparison. Can only say the cars I did use it in performed well over the years. This was back in the days of mechanical fuel injection btw, never used it in a later TDI/TDCI etc.

As Luke says, probably little/no benefit over good quality fuel. 

1 hour ago, Eric Bloodaxe said:

Auto Express recently had this article:

https://www.autoexpress.co.uk/car-news/33200/fuel-additives-are-waste-money

I used to use Millers for years, having been recommended. Don't know if it ever made any difference though, never did a comparison. Can only say the cars I did use it in performed well over the years. This was back in the days of mechanical fuel injection btw, never used it in a later TDI/TDCI etc.

As Luke says, probably little/no benefit over good quality fuel. 

 

I too use Millers additives and have done for many years. Used their VSP (Lead replacement) on my old Metro, then diesel clean on both of our mk1 Fabia diesels (1.9 PD TDIs). I occasionally put petrol clean in my Fiesta, but find having to use the funnel every time is a pain. I only use Shell fuel anyway. I'd suggest to you double dosing for the first 1 or 2 tankfulls, then single after that. It not only cleans the fuel system, but also adds more cetame. It can be cheaper than using super-diesel (VPD etc).

We have used their oils for many years, since mid 90s on our AX and still do. Millers produced the best oil for Rover A-series (mini/metro), as it had both engine & gearbox additives in. I used to buy the stuff from a local motor factor at trade price, but now order online from Opie.

35 minutes ago, Jim H said:

 I used to buy the stuff from a local motor factor at trade price, but now order online from Opie.

Yes, my local source also dried up,which was partly why I stopped using it. Plus by then fuels were claimed to have improved. I also used their oils when still doing my own servicing.