After just having my 2011 1.6 TDCI Mk2 Ford Focus on 80k fully serviced and MOTd (no advisories) I filled the tank up and took her for a drive - everything running smoothly with no dramas. As the car had been sat prior to its service I decided it's be a good idea to drop a Redex DPF cleaner in there (the one shot per tank one in the silver bottle) my tank had about a fifth of fuel missing. Upon using, car actually felt quite perky and I was pleased, I decided to take it out for a proper drive getting up to motorway speeds. After about a kilometre an engine malfunction appears on the dash. I experienced no loss of power, no noises, no nothing. Car appeared to drive identically. Regardless I pull over. Upon restarting the car (so I can double check on what fault I just got) I noticed the dash was clear. It made a single beep when I received the fault and then stopped but now its completely gone. The only thing I can think is that the bottle of Redex inside the not full fuel tank had caused the issue. There was a garage around the corner so I rolled down to it and topped the fuel up. Upon starting the car again I find that once again the malfunction has disappeared? I chance it and drive home staying under 50 without any problems. Could it have been the Redex? Is that a thing? Any thoughts appreciated!

1 hour ago, TurboDai said:

... Could it have been the Redex?

No, OK, I'll rephrase, very highly unlikely...

1 hour ago, TurboDai said:

After about a kilometre

I didn't know that Wales had gone metric, but then again I can't say the place names either 🤣

I’ve got a 2018 1.0 litre Focus Vignale.  After having a number of VW golfs where I regularly used Millers fuel additive with no problems, I found that every time I tried the millers in my Focus it would throw a power train fault after some time!  This resulted in numerous dealer visits, where they had to  reset the PMC.  I’ve now given up with fuel additives and had no further problems.

58 minutes ago, StephenFord said:

No, OK, I'll rephrase, very highly unlikely...

Thanks for the reply! Care to explain? I've now read a few threads that have said the same thing - one from a bloke in a POLO who quite frequently accidentally 'double doses' each time he gets an engine fault. I realise that on the the bottle it says NOT to do so and that only every 3000-5000 miles (or something) could this possibly be why? I use the standard redex diesel occasionally and maybe the combination of residual redex plus the DPF cleaner plus my tank not being completely full could all possibly contribute to the engine thinking its eating something other than fuel? Thanks again for the reply. 😄

6 minutes ago, SteveP1041 said:

I’ve got a 2018 1.0 litre Focus Vignale.  After having a number of VW golfs where I regularly used Millers fuel additive with no problems, I found that every time I tried the millers in my Focus it would throw a power train fault after some time!

No kidding? I've now read a few threads saying the same thing on various vehicles - one chap and his POLO have the exact same problem. He said that he'd occasionally forget and drop a whole bottle in (double drop) and it would religiously cause a fault.  My only guess is that the fuel is running a little rich with Redex which in this case isn't isn't dangerous thing but triggers something nonetheless. Thanks for the reply! Perhaps its time to hang up the ol' Redex!

Think of it like 'the' vaccination - you either believe it works, or it doesn't. If you believe that a 'fuel additive' doesn't work, don't use it. Millions of cars survive their whole life without using one, though I'm a fan...

My mum's 2003 Toyota Yaris is still going strong - never used an additive. (proof they don't work)

My own Focus, 110,000 miles, regularly uses a fuel additive (proof they work)

(I've always been a sucker for a good additive advert - started using Slick50 in the 70s!)

9 hours ago, TurboDai said:

I use the standard redex diesel occasionally and maybe the combination of residual redex plus the DPF cleaner plus my tank not being completely full could all possibly contribute to the engine thinking its eating something other than fuel?

Have to wonder how this DPF cleaner is intended to work...  Fuel is all burnt in the cylinders (with the exception of DPF regen)...so what's reaching the DPF to clean it?  Or is it intended to burn hotter than regular diesel to create higher EGT's...if that's the case, maybe the DPF temp sensor is throwing the fault.  You'd really need to have the fault codes read with Forscan to see what's occurring, and whether we can attribute that to the additive or not.

My personal opinion is NOT to use additives on modern engines, much better off running the tank down and then sticking half a tank of premium fuel in instead.

1 hour ago, StephenFord said:

started using Slick50 in the 70s

Ah !! "Slick50" now that takes me back. It's the only time I've used an oil additive and I can say it worked 100%

At the time I had an "A" Reg Ford Orion 1.3GL and in the morning trying to select reverse gear was always difficult, and first gear wasn't much better until the car had done a couple of miles and then all would be good. One day I saw that you could buy Slick 50 gearbox oil additive. So after messing about getting some oil out of the gearbox, I put the Slick 50 in and waited to see if it would make any difference. In less than a week the gearbox was perfect and no more problems with reverse gear first thing in the morning.

My friend also had a 1983 Orion 1.6 Ghia with the same problem, and so we did the Slick 50 gearbox additive on his car and again in less than a week the problem of the sticky reverse gear was fixed. We both went on to put the Slick 50 engine oil additive in which might or might not have made a difference but we thought since it worked on the gearbox then it wouldn't do any harm trying it in the engine.

1 hour ago, TomsFocus said:

My personal opinion is NOT to use additives on modern engines, much better off running the tank down and then sticking half a tank of premium fuel in instead.

Hey Tom, on your advice, guess what I gave the old girl on the way home this morning! She better not get use to it, dam expensive LOL

13 minutes ago, StephenFord said:

Hey Tom, on your advice, guess what I gave the old girl on the way home this morning! She better not get use to it, dam expensive LOL

I've never seen a glove dispenser like that before!! 

1 minute ago, TomsFocus said:

I've never seen a glove dispenser like that before!! 

Neither have I, and to be honest, didn't even notice it till I was replacing the nozzle back on pump!

BP? It’s more of a hand size bag than a glove , does a job though. I’m paying £1.31 litre unleaded at the moment. At First lockdown was £1 . Really notice the difference filling up. I refuse to pay for the premium unleaded not cause I’m tight but just always thought it only benefited sports cars.. 🤔 

9 minutes ago, Alex.S said:

BP? It’s more of a hand size bag than a glove , does a job though. I’m paying £1.31 litre unleaded at the moment. At First lockdown was £1 . Really notice the difference filling up. I refuse to pay for the premium unleaded not cause I’m tight but just always thought it only benefited sports cars.. 🤔 

I use a small BP station but haven't seen those so far...then again, it doesn't even have pay at pump!  I've been taking my own glove since the pandemic.  Never used one before, always enjoyed the way the diesel lubricated the steering wheel giving a bit of jeopardy to the drive home...

Premium fuel contains more additives than regular, some of which are detergents to clean the fuel system, so if that's what you're after from an occasional Redex then it's a good alternative.  You are right that the higher octane level isn't likely to be noticeable in 'normal' cars so no point using it all the time.

28 minutes ago, TomsFocus said:

I use a small BP station but haven't seen those so far...then again, it doesn't even have pay at pump!  

The BP I used the other day does have those. Never bother with them though, just have a good dollop of sanitizer and then a handwash when I get home.

No pay at pump though. That's been a very good feature of places like Tesco during the pandemic but I suppose the reason most don't do it is so you go into the shop and they can try and sell you something!😀

8 minutes ago, Eric Bloodaxe said:

The BP I used the other day does have those. Never bother with them though, just have a good dollop of sanitizer and then a handwash when I get home.

No pay at pump though. That's been a very good feature of places like Tesco during the pandemic but I suppose the reason most don't do it is so you go into the shop and they can try and sell you something!😀

I've used the BPme app to pay for the fuel for the last couple of years...as if I'm going to step inside a kiosk full of diseases!