Diesel Additives?

[tixntox]

I'm about to buy a 10 year old turbo diesel runabout (Hyundai IX35). Do we have any recommendations or advice with regard to additives for clean running etc. It's been 20 years since I had a (very old school) normally aspirated diesel and I used the "company" additive which was very good (seen the results of side by side comparisons). I don't want to buy "snake oil"! Thanks in advance.

[Andyg]

I'm about to buy a 10 year old turbo diesel runabout (Hyundai IX35). Do we have any recommendations or advice with regard to additives for clean running etc. It's been 20 years since I had a (very old school) normally aspirated diesel and I used the "company" additive which was very good (seen the results of side by side comparisons). I don't want to buy "snake oil"! Thanks in advance.

https://uk.bestreviews.guide/diesel-...SAAEgIQsvD_BwE

[Kingstepper]

https://uk.bestreviews.guide/diesel-...SAAEgIQsvD_BwE

Wouldn't trust that site, no actual reviews and probably just making money via Amazon links.

I've always assumed the additives were all snake oil TBH.

[oldoakknives]

Difficult to find a garage where they offer you a couple of shots of Redex these days.

[sickie]

Forte additives are pretty good. STP is another.

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[walkerwek1958]

Can someone enlighten me, what do these additives do? I run a Diesel Jag XF 3.0 that’s 11 years old and runs as sweet as a nut.........am I missing a trick?

[David_D]

Can someone enlighten me, what do these additives do? I run a Diesel Jag XF 3.0 that’s 11 years old and runs as sweet as a nut.........am I missing a trick?

What diesel do you use? Supermarket or “premium”.

I switched to Optimax when I decided I was hanging on to my car in the hope it looks after the engine.

Noticed zero benefit in mpg or performance which are often reported.

EDIT: https://www.autoexpress.co.uk/fuel/1...premium-petrol

Premium diesel

Because diesel engines don't ignite fuel to create power (fuel is added to the air that is compressed instead), premium diesel doesn't usually feature a higher octane rating. Instead, this more expensive super diesel will feature chemicals in its mixture that are designed to shift soot deposits and other oily build-up from within the engine's fuel system.

So why choose super fuels?

If you drive an ordinary mainstream car, then there's not much point in paying extra for premium fuels. Your car has been set up to work properly using standard petrol and diesel, and fuel companies have created their regular gas to work effectively in your engine.

However, if you drive a diesel car, there's no harm in running a tankful of super diesel through the engine every 1,000 miles or so. This should clear out any oily or sooty deposits from the engine and fuel system, and will help your car to be more efficient and economical when running on regular diesel, as the fuel system will be clearer. In the long run, paying an extra 5-10p per litre for super diesel every now and again could help to avoid costly future repairs if your diesel engine packs up.


The real benefits of super fuels can be had by owners of performance cars, even hot hatchbacks. While many of these cars will work perfectly well on regular petrol, you should be able to tell the difference if you fill your tank with high-octane fuel. Improved throttle response will be the clearest indication of its benefit, while the engine should rev more freely and should deliver more power.

[Bonzodog]

I’ve ran diesel cars for years,never used additives,never had a problem so far.

[tixntox]

I was a transport manager over twenty years ago and we tested diesel additives on similar vehicles doing similar jobs over a 12 month period. At the end of the time, the engines were stripped and rebuilt. The engines with additive had much less carbon build up and an analysis of the mileages showed a 2-4% increase in efficiency. The vehicles were swapped between routes and drivers to ensure accuracy. The decision to use the additives was made and the lack of breakdowns, due to injector failure, also became apparent. Most drivers said that they couldn't see any difference but the figures proved otherwise. Unfortunately, the product that we used is no longer on the market but my thread was to see if there is a modern product that actually works. Shell state that their V-Max has additives and that they have been proven to work. I don't suppose on my 10 year old runabout, that it will make too much difference but every little helps in terms of reliability. Thanks for the answers so far.

[E_2_Right-Force]

A very long time ago i owned an ex-GPO Ford escort diesel estate - remember when GPO vehicles were bright yellow?
At MOT time it would invariably fail on emissions, one particular time i remember the reading on the meter to be 9.9 on a meter that went up to 9.9....*
I think the pass rate at the time was something like 2.5.
The MOT tester suggested i ran the fuel tank as low as i dared and then put in a full bottle of Comma `Diesel Magic` and re-test.
I did, and the emission reading was then well below the passs rate.
I assumed all these jollops were just snake oil and was surprised to see it`s still available, but they do (or did) have at least some positive effect under certain conditions....


*before you all whinge about the planet being poisoned by noxious fume-emitting old bangers - i don`t give a shit.

[oldoakknives]

My uncle used to do very high mileages as a service engineer and he always kept a record of mileages and fuel used. He used Slick 50 in the oil of his car and said there was a noticeable improvement in MPG when he looked at the figures. A lot of the other additives often seem to be a panic buy when something is already worn out/going wrong in the engine or gearbox.

[Andyg]

My uncle used to do very high mileages as a service engineer and he always kept a record of mileages and fuel used. He used Slick 50 in the oil of his car and said there was a noticeable improvement in MPG when he looked at the figures. A lot of the other additives often seem to be a panic buy when something is already worn out/going wrong in the engine or gearbox.

i used to put Slick50 into my old 83 Citron BX. By the time I sold it, it had 189k on the clock, and know it did at least another 50k. The magic ingredient was PTFE which acted as an additional lubricant.

Regarding diesel additives, the most common is AdBlue which used to reduce Nox emissions. However there are others, like Millers, that include detergents to help clean the injectors, and generally remove crap around the valve gear.

[Franky Four Fingers]

i used to put Slick50 into my old 83 Citron BX. By the time I sold it, it had 189k on the clock, and know it did at least another 50k. The magic ingredient was PTFE which acted as an additional lubricant.

Regarding diesel additives, the most common is AdBlue which used to reduce Nox emissions. However there are others, like Millers, that include detergents to help clean the injectors, and generally remove crap around the valve gear.

Ad-blu doesn’t go through the combustion process and isn’t a diesel additive, its injected upstream of the DPF, it’s different to fuel additive which is poured in the tank and goes through injectors, pumps etc.