Diesel fuel additives

[Buckman]

In the past every couple of months I have added Miller diesel engine cleaner which is supposed to clean the fuel system and injectors, but I have not done so recently. By adding the additive to me it seemed as if the vehicle was running quieter. I am not sure if it improved economy.

Recently the car has very occasionally experienced a "flat" spot while travelling almost as if the car is coasting and car slows down until I give the accelerator a gentle touch. The issue disappeared after a long tow, but may have occurred again yesterday.

Taking into consideration over the past two years the car the car has only done 14000 miles and less than 7000 miles in the past year. Many journeys have been maximum of 14 miles on A roads where speed kept to about 50mph. I am now wondering if perhaps the DPF is not getting the opportunity to regenerate properly or due to low mileage the injectors or perhaps fuel line needs cleaning? I am guessing. The car is 10 years old with 73K on the clock.

At the moment the tank is about third full. Choice is paying the extra for a tank full of Supreme or buying an additive to run through and hopefully clean the system. The difference in cost for the Supreme or buying the bottle of additive cleaner is almost the same however250ml of the additive is only good for 60 litres and my tank is a lot bigger so the additive costs more.

I used to buy Millers from Halfords, but they no longer stock so thinking of either Forte or STP DPF regenerator additive and also an engine cleaner. Maybe use them plus the Supreme fuel. Any thoughts?

 

[JTQ]

With a DPF with now one assumes 75K miles of accumulated ash and goodness knows what else in it I would not be adding anything to the fuel. These have a finite life, shorter with injector troubles, very much shorter with lower spec engine oils and very expensive to replace.

Lend it to a 21-year-old boy racer, or relive those days, with limit free motorway driving. That will help burn anything burnable in the DPF and turbo nozzle vanes

I suspect the additive will stabilise the combustion at low crankshaft speeds, giving a genuine less harsh characteristic, though do less for you as the revs increase.
The mentioned issues IMO stem from our domestic cars having too big diesel engines so not thrashed in the way they like and white van man drives their vans.

 

[Jcloughie]

All cars I have had the manufacturer says not to use any additives. In fact a Peugeot said it might invalidate the warrantee. So I have not. I am doing half you milage, my car is 9 years old and 78,000 miles. And runs sweetly. It must regenerate every so often, but you would not know it. Yesterday I drove to your area to visit Elgars birth place. Biggest run it has done in a long time. At one point I needed to floor it to pass a tractor and was very impressed for a 135 hp car.

John

 

[otherclive]

If the price is about the same I would opt for Premium fuel,, but only using the car for relätively short journeys might not achieve the best outcomes. So as said by JTQ an Italian tune up is needed.

 

[otherclive]

All cars I have had the manufacturer says not to use any additives. In fact a Peugeot said it might invalidate the warrantee. So I have not. I am doing half you milage, my car is 9 years old and 78,000 miles. And runs sweetly. It must regenerate every so often, but you would not know it. Yesterday I drove to your area to visit Elgars birth place. Biggest run it has done in a long time. At one point I needed to floor it to pass a tractor and was very impressed for a 135 hp car.

John

You will be possibly approaching the time when the residual ash build up in the DPF may necessitate a replacement DPF. But it’s not an exact science as all cars are different as are their owners driving style.

 

[Buckman]

If the price is about the same I would opt for Premium fuel,, but only using the car for relätively short journeys might not achieve the best outcomes. So as said by JTQ an Italian tune up is needed.

We are off for the weekend to a CL near Lutterworth and mostly motorway driving along M42 and M6. So will fuel up with Premium and floor it as much as possible while towing.

 

[Buckman]

Extract from a report by the former Rob-Jax who was a respected member of thsi forum;

After market additives
After market products like Millers improve the cetane rating of standard diesel, but only when the engine is cold - interestingly it doesn't help a hot engine - so cold starting is usually quieter but no difference to a hot engine - and Millers does provide good, additional pump lubricity.

Self Tuning Engine Computer
So, if your diesel engined car "self tunes" then try Shell V-Power, BP Ultimate, Total Excellium - I see between 3% and 5% improvement in fuel consumption. My Mercedes C270 returned 52.8 mpg driving from Rotterdam to Wendover yesterday - on Dutch Shell V-Power - 320 miles at speeds of around 60, 70 and 80 mph depending on the country / road speed limit - using the electronic speed limiter. If not, stick with the regular diesel fuel, and add Redex or Millers at the recommended dosage level - adding more won't improve the performance. And don't be dismissive of supermarket fuel, it can and often is identical to branded fuel.
And if you add Redex or Millers or switch to a branded fuel, then any change to the cleanliness of the injectors won't show itself for quite a few hundred miles, but pump lubrication and maybe a higher cetane rating will show an effect much sooner - depends how much old fuel was in the tank and fuel lines - and how much the old fuel dilutes the action of the new fuel.
So is there a difference between supermarket and branded fuel ? - there can be - but often there isn't.

 

[Woodentop]

The usual guidance to at least part if not fully clean a DPF is a 30 minute run at a steady 2000rpm keeping as steady speed as possible.
However any car fitted with a DPF should have a monitoring system that will make the item run hotter than usual for a while to clean it. You can tell when it is being done - the tickover revs may be elevated a bit to around 1000rpm, and the fan(s) will keep running for a while after you switch the ignition off.

 

[Raywood]

If you want the Millers additive it is available from Amazon.

 

[Buckman]

Thanks. Looking at the price of it, I might as well fill up with the premium fuel as on 30L the difference is about £6.

 

[Bluetonic]

We are off for the weekend to a CL near Lutterworth and mostly motorway driving along M42 and M6. So will fuel up with Premium and floor it as much as possible while towing.

Ashby Lane Farm?

 

[Buckman]

Ashby Lane Farm?

Not Ashby Lane but something Orchid a bit more east. We have to go to Welford for a repair to our satellite system.

 

[Hutch]

Not Ashby Lane but something Orchid a bit more east. We have to go to Welford for a repair to our satellite system.

What another problem with your caravan, have you thought about going for Bed and Breakfast, weekends.

 

[Bluetonic]

Not Ashby Lane but something Orchid a bit more east. We have to go to Welford for a repair to our satellite system.

Ah, not tried that one yet, we are at Ashby lane from Friday 😀

 

[Buckman]

What another problem with your caravan, have you thought about going for Bed and Breakfast, weekends.

Not the caravan this time.