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Will it float?
Ninehigh - 31/8/10 at 10:13 AM

I've been looking at these people running vegatable oil in their cars and being a bit miffed that mine can't and I have all this cooking oil that I could chuck in the tank. I'd like to experiment by putting a small amount in (say 1 litre old veg/sausage oil to about 60 litres good diesel) and seeing what happens.

I was thinking worst case scenario it runs like a bag of s**te for about 50 miles but then I realised that worst case scenario is the oil floats on the diesel and starts to run like a bag of s**te at random when the diesel has run out and there ends up being 40 litres of c**p because I thought it's being ok.

So will old cooking oil mix in with the diesel or sit on top?

Miks15 - 31/8/10 at 10:16 AM

why not fill half a cup with diesel and half with oil, leave a while and see what happens?

Ninehigh - 31/8/10 at 10:19 AM

quote:
Originally posted by Miks15
why not fill half a cup with diesel and half with oil, leave a while and see what happens?


You know that's a good idea, and I have some in a can in the back of the car (abusing the "5p per litre off" voucher)

Also I imagine it would mix as I'm driving, so the only major problem here would be if the oil sinks and it'll be the first thing through on a cold morning...

blakep82 - 31/8/10 at 10:20 AM

don't think the oil will float? pretty sure it mixes together ok, otherwise no one would be able to do it properly

mcerd1 - 31/8/10 at 10:33 AM

what kind of car would you want to run it in ?

MikeR - 31/8/10 at 10:44 AM

All diesel you buy now is a blend of diesel and bio diesel. Usually in the uk around (i think) 5%. In some places in Europe its up to 15%.

The problem running straight bio is making sure its 'made' properly. The problem running straight veg oil is that its 'thicker' than diesel. Running a mix is ok cause the diesel thins the thicker veg oil. In summer as its warm the veg oil is thinner anyway. In winter veg oil (and diesel) get thicker therefore in winter they add stuff to keep the diesel thin and your veg oil blocks the pipes in the car.

Also, be careful with the fuel pump your running, (none common rail) Bosch pumps are fine with veg oil, lucas ones die. If you've got common rail ..... good luck, i'd stick with low percentage mixes, especially as the replacement pumps are so f'ing expensive.

marcjagman - 31/8/10 at 10:52 AM

I drove all over europe a couple of years ago, before I left I mixed 50% veg oil in my tank, no problems. Go for about 25% oil and you will be okay.

l0rd - 31/8/10 at 11:02 AM

Take a pint

Put half diesel and half oil and check how well it mixes.

[Edited on 31/8/10 by l0rd]

Ninehigh - 31/8/10 at 11:14 AM

quote:
Originally posted by mcerd1
what kind of car would you want to run it in ?


Tdci mondeo, Ford's own manual says no more than 5% mix of biodiesel and when I started running it on pure bio it ran like a sack of ****

However 5% is 1 litre in 20 right? So 1 litre in 50-60 is less than 2%. Not much but it just sits there until someone throws it out

coyoteboy - 31/8/10 at 11:20 AM

Veg oil is not bioD.
BioD is ok to ~30% on many engines, but some less.
Veg oil is only OK in non-commonrail engines.

Veg oil in commonrail engines = pump death (maybe not immediate, but much more rapidly reached), injector contamination (with pump bits) and latterly car write-off as parts cost is vast.

Don't bother unless it's a mechanical injection system.

[Edited on 31/8/10 by coyoteboy]

steve m - 31/8/10 at 11:48 AM

So with a Tdci mondeo, that is aa common rail its a no no ??

As i had thought about adding some in small quanties

Also (hijacking this tread sorry) can used engine oli be used in a diesel fuel system, obviously cleaned and filtered ??

Steve

coyoteboy - 31/8/10 at 11:54 AM

If it's any sort of an electronic injection system I'd stay WELL away from it. They're very finely tuned electromechanical systems designed to work in tight tolerances with known fluids, is mixing in cheap/free/rubbish stuff to save a few quid here and there really worth the risk? I mean an oil change is what, just over a gallon. So you're getting ~40 miles for free, at the risk of injection system failure. Doesn't seem like smart risk management to me. Yes the car will run on engine oil, but it has different viscosity, different byproducts, different combustion properties and is never going to be as clean for shoving through your injectors as normal D - take a look at the holes in the end of a commonrail/direct injection injector - the holes are literally on the micron scale. Not like petrol injectors where they're hundreds+ of microns, the D needs to go through seriously small holes at seriously high pressure to be adequately vapourised. Injectors are ~£100 a pop. There's being frugal/recycling, and there's taking silly risks. To me it's a silly risk, but your mileage may vary.

jimmyd - 31/8/10 at 01:32 PM

Mondeo is common rail. I wouldn't risk it these things do not like unclean fuel of any type. As mention on a previous post you will kill the pump, if not now in a little while.

MK9R - 31/8/10 at 02:51 PM

don't stick it in a mondeo, you need the older style non common rail diesels. I ran a xsara on 50/50 mix with cooking oil for 1000's of miles without a problem, but then asda cottoned on and the price of vegi oil went up to the same as diesel so not worth it any more. If you are using waste vegi oil thats been used to cook with you first need to clean it, including removing all the water.

JoelP - 31/8/10 at 06:45 PM

apparently you can add a touch of petrol to thin it a bit. The main thing is as said above though, is it new veg oil or used?

Deffo mix in a jar and see what happens - especially if you try to pour them seperate, if you see what i mean. Thouhg i myself would be very cautious about trusting them to mix themselves.

hillbillyracer - 31/8/10 at 07:39 PM

Another thing to watch for apparently is when you start to use it the crap that's been on the bottom of your fuel tank no causing any problems floats more in the veg oil & you go can through a few filters before it clears it through!