Mazda CX-3 Forums

The wife has just had the car[cx3 1.5d] trucked into the mazda dealer after losing power while driving, we had a phone call saying no faults found except a blocked fuel filter and that was not under warranty £95+vat and they said not to use cheap fuel.

Now the car is only three months old and just over 2000 miles....is this normal?....She decided to ring mazda customer service direct and it took about two minutes for them to say they would cover the cost so that's brilliant news but I do now have a worry about this fuel filter, is it better to not use supermarket fuels at all or once in every four fills?

Oh, the old chestnut of supermarket fuels. As far as I know the fuel comes from the same refineries as the brand leaders, the difference is the additives. I cannot comment on the CX-3, neither the petrol or diesel are performace cars. But I do have an opinion at the other end of the spectrum. My Nissan 370z has to run on super grade. Shell V power, Tesco Momentum work great, BP Ultimate is borderline. I have tried many others but remain with Shell or Tesco. This is not a "placebo effect", I really can tell the difference. In fact I am running the CX-3 on Super, just for the heck of it and hang the expense. Waste of money? maybe, but after paying 24 grand for the car, what's a few extra quid.

There are many strong and opposing views on the subject of supermarket fuels.

As I understand it (and I'm no expert on the subject) the standard base fuel is all the same and has to meet British Standards so you can mix different brands in the same tank. What varies is the additives package of extra ingredients that goes into the base fuel to help keep the engine clean and improve lubrication etc. Each fuel company will have its own additives packages.

The other thing that can make a difference is how the fuel is stored at the forecourt. If a particular forecourt has sludge in their tanks then some of that can be transferred to your tank.

I used to use a local supermarket diesel, but on trying BP, I found the engine seemed to run more smoothly, but it may be psychological.

As a driving instructor I covered on average 40,000 miles a year and I did that for twenty years using Tesco fuel.

Never had any problems fuel related in all that time, the old chestnut again, it all comes from the same refinery.

How dare the dealer try to charge you for a blocked fuel filter

After only 2000 miles that’s only 4/5 tanks of fuel and one of them would be the dealerships

I would be asking them what material blocked the filter as it could be something left in the tank during manufacture and it may need flushing out

Good idea, I will ring them...thanks guys

Well that went well, girl on service reception said she would put me through to the fitters but the phone got cut off, but what she said before putting me through was strange.
I asked if she could tell me what blocked the fuel filter and she said pig fat? what I thought and she went on to say that Diesel is normally made with rapeseed oil as an additive but it is getting switched for pigs fat which blocks the filter when its cold.....is this real?

jtonline mentions the cleaning aspects of modern fuels, if only that was true nowadays. The Skyactiv engines, like many other modern engines use direct injection into the combustion chambers therefore the fuel does not pass through the inlet valves but directly into the combustion chambers. The effect of this is that the inlet valves are no longer cleaned by the fuel as they only provide the air (and a bit of crankcase gases - to relieve pressure) so over time the inlet valves will become coked up and performance will suffer. The only way to sort this long term mess out is to have the valves cleaned with walnut blasting, yes real walnuts as they are very hard but do not damage the combustion chambers or valves.

Handy Andy, I think you will find it is walnut shells which are crushed and ground into various grades, which are used as the blasting medium.

DaveG wrote: ↑Tue Jan 09, 2018 3:14 pm Handy Andy, I think you will find it is walnut shells which are crushed and ground into various grades, which are used as the blasting medium.

Yes, I meant the shells, I eat the contents, they are tasty