Good evening All

If you're thinking of using Redex, STP or any other type of fuel cleaner in your Mk7 Fez, DONT!

I stupidly added a bottle of STP fule cleaner to a full tank of petrol, once the fuel went through the system my EML (Engine Management Light) came on. It appears the Oxygen sensor (aka pre Cat lambda sensor) became faulty all coz the fuel cleaner messed up the fuel/oxygen mix. A replacement sensor cost £70 from Unipart and labour inc light reset cost me £30.

I'm gonna write to Redex and STP to say to them that their cleaners aren't suitable for modern engines....not sure if its gonna achieve anything but worth a try.

Erm....why did you even bother putting that into the system anyway? It wont give you any benefit being such a new car

Mark - please dont tell me off, I know I balls'd up. I put it in hoping it will keep the engine clean....how wrong I was....never again

Hi Kabz

Sorry to hear of your problem with the cleaner. I must admit that having a diesel I haven't used the REDEX stuff but I have used a variety of fuel additives over a period of 12 months and 62k miles since the car was delivered brand new.

I must admit that every 25k miles to using "BG 244 Diesel" additive which in my opinion, well in fact most peoples opinion, is the best fuel cleaner on the market with no ill effects at all. I even add 2 Stroke oil to the diesel on every fill now, just because I have a tuning box and do a lot of motorway miles, its just a bit of security and upper cylinder lubricant is the only reason I use it. I average 1200 miles per week and the only issue I've had, is that at 30k miles the fuel filter gave up the ghost causing fuel issues and had to be replaced.

With 60k miles on the clock now after 12 months, the engine is like new, averages 48-52mpg which is excellent considering what I do with it.

I can only think that it was a coincidence that your Oxy Sensor gave up and may not have had anything to do with your fuel additive. In the early days I always used Millers Diesel goo and would get thro a bottle every 6 weeks just because of the mileage. The cost of the stuff and how much I was shifting was the only reason I stopped using it, and of course I then found out about the BG products, believe me they are good.

Tone - it wasn't a coincidence, I changed the O2 lambda sensor a few weeks before I used the cleaner, reason I changed the sensor was coz I was getting a remap and as my mpg was low at the time I thought the sensor was faulty. I put on a brand new one and it was a week after using the cleaner stuff that the sensor became faulty so I know it was definitely the cleaner thats not healthy for the mk7 Petrol cars. Oh well, I got the sensor changed and light reset, I've done about 25 miles since and touch wood the EML light hasn't come on again, I'm averaging 32/33mpg.