Engine Oil additives - are they worth it?

[flyerdave]

Hi all - been looking through past topics on this issue - some seem to like them - others don't

May be an update on what people are doing at the moment may help me to make up my mind about them.

Also interested in where you buy your fuel and why. Is supermarket fuel as good as say Shell or BP?

What do you do?

[Welly]

Additives in the oil - if you mean a flushing agent? then if the car's always been flushed each time then I'd say carry on with it but if you don't know then be careful as you may shift a lump of old waxy oil and block an oil-way.

Additives which are supposed to reduce friction etc are all bollocks imo

Supermarket fuels are debatable as some people seem to think it's the very same stuff that Texaco and BP use but others argue it is definitely cheap and possibly inferior to the big names.

Diesel fuel seems the same all over to be fair, I tried some V=power diesel once and couldn't really report anything one way or the other.

Petrol from supermarkets has come under a fair bit of criticism and some report fewer mpg's and increased pinking/missing before switching to Shell etc..

[swiss]

I can't report any noticeable difference between Tesco smart price diesel and the big brand regular stuff, and I was never rich enough to justify the various Super Opti-Awesome premium fuels. I am told though that the BP premium stuff has extra detergent in it, and it was suggested that this could help with emissions testing. Personally I just threw in some Redex whenever I could be bothered.

What I do know is that Morrison's B30 bio-diesel gave me better MPG. Dino diesel would get me 600 miles to a tank, pretty consistently, whereas the B30 got me 700. I don't know the scientific explanation, something about energy density probably or the transperambulation of pseudo-cosmic antimatter, but it definitely worked.

Unfortunately Morrison's learned that I liked the fuel and stopped selling it, just to spite me.

Regarding the oil, unless you know it's been flushed on previous changes just get the engine nice and toasty then drain and refill as usual. The board has many threads on which grades and brands to use, and FYI you can get good quality oil on the cheap if you have it delivered off t'interweb.

[highlander]

My 1.8 petrol seems to like Shell's fuel best - the car seems to be a little more sprightly and I definitely get more mileage from a tank of normal Shell fuel than I do anything else.

Shell's V-Power is another matter - I got no performance or MPG gains from that at all.

Now that Shell have replaced their normal fuel with this "Fuel Save" stuff, I have yet to complete a tank's worth. I'm going down to York at the end of this month for my Ferrari/Lamborghini track experience (30th birthday present) so I'll tank up with Fuel Save and see what that gets me.

[Welly]

On many cars it has been found that the extra £££'s spent on 'better' fuel or even higher Octane fuel can pay pack in higher mpg's. You certainly get better mpg with 99 Octane stuff.....

[Doggy]

I did a few comaprisons on my last two 3.0 gas guzzlers - there was a definite improvement in mpg, but in every case I tried, (6 or 7 tankfuls), the extra cost almost exactly equalled the extra range, i.e. the same cost per mile!

After that, I restricted it's use to the final visit to the pumps before the prospective new owners turned up for the test drive.

[DiscoPol]

My big BMW loved the hi-octane stuff, but at 4.4 Litres it loved any fuel, the "super unleaded" always gave me another 2-3mpg more on my regular trips over the Pennines, 2-3 mpg is a lot when you think it only gave me 22 mpg combined at best, but as others have said the extra cost just about equals the extra mileage.

Now in the HDi all the "super diesel" seems to do is make the knock/ticking from the injectors worse, it doesn't seem to improve the mpg, not that im complaining about the pugs frugal nature at all, im almost constantly surprised it manages to give me the figures it does and that's on Polish roads with fuel from the cheapest suppliers,

so who knows the quality I am currently paying 4.10 zloty (83p) a litre and it still gives me 5l per 100 km (56.5mpg)
it is making it hard for me to get rid of the old girl TBH

[Doggy]

Keep the faith, Polski

(You won't get anywhere near that mpg wiv one of them Chelsea tractors you wuz after).

my 406 seams about 3 mpg better since the remap

[DiscoPol]

(You won't get anywhere near that mpg wiv one of them Chelsea tractors you wuz after).

i know but winters coming, the pug gave up last year in Manchester at -14, that's nowt compared to the -20 to -30 that is normal here and when the snow comes here in Poland it really comes

Oh and i wanted to add on long journeys, like when i head back to the uk for stuff, i add millers eco-max diesel additive and it gives me about another 4-5 mpg, but then we are talking about a 4500 km round trip and the wheels hardly stop moving for 24 hours at a time, so that might be affecting the mpg figures too, but at £12 ish a bottle i think it just about pays for itself as it doses at 1/1000 i think so only 70ml is per tank full. There is a noticeable pick up in the engine after the first tank with it in goes through, but i do only use it on the trans euro runs now as i cant get it here so im saving it

[mjb]

I used to drive my old tubby in exactly the same way every day over a 120 mile round-trip and my mpg was consistent to 0.1mpg every day.

I tried many fuels (except Shell) and I found BP Ultimate fuel gave the best mileage but BP standard provided best value. Now I drive a V6 I've discovered Shell V-Power racing 100 RON (probably not available in this country) gives massive economy (over 800 miles on a tank!) but here I fill up with BP Ultimate as there's no Shell nearby and Ultimate's the best mpg per £

Asda fuel dropped fuel economy by about 20%

[Captain Jack]

i know but winters coming, the pug gave up last year in Manchester at -14, that's nowt compared to the -20 to -30 that is normal here and when the snow comes here in Poland it really comes

That's because in England we don't change our diesel to winter type - that is, with additives to stop it from freezing/waxing. In Poland, they most cetainly do, so I'd be surprised if it stopped working on Polish winter diesel

[Doggy]

Mine has an electic heater to heat the fuel line, which I believe operates whenever the fuel temp is < -3. Not sure if all HDi's do, (I'll check on ServiceBox when I get a mo).

If yours doesn't, Polski, it might be worth adding.

Reference Description Quantity Price - VAT Price + VAT Total + VAT
00001579Y6 FUEL REHEATER 20.08 GBP 23.59 GBP 23.59 GBP

Some HDi 90's have them, others don't?????

[flyerdave]

I can also confirm that Asda fuel gives less mileage. My local Shell garage maintains the same price as Asda (not sure if they water down the fuel but I doubt if they would be allowed to).

I am going to Cumbria in September and will do some tests of my own then.

About engine oil additives - I think that I will just flush the engine with some cheep engine oil. Should I use a thinner grade to do this?