veg oil

[straggler]

Hi all,

I have a 1996 406 1.9 TD with the Bosch fuel system. I've been experimenting with running it on a veg oil/diesel mix and it all seems fine so far, apart from seeming to run ever so slightly rougher when on a high percentage of veg oil, plus a bit of a misfire for the first five or so seconds after a cold start.

I drove it to Berlin a few weeks ago and took a load of lovely cheap sunflower oil from Tesco with me. I was intending to use a 50/50 mix but couldn't be bothered in the end and just chucked in 35 litres of veg oil. The car ran with no problems at all, apart from the slight misfire when stone cold.

Do I need to do any additional/extra maintenance if running it on veg oil long term? The car is in good nick and I'd like to keep it running as long as possible but don't want to spend too much money on it if I can avoid it. I know that I should be using a higher proportion of diesel in the winter due to the thickness of the veg oil but I'm lucky enough to be spending the UK winter in a warm country so the car is only used March-November (I fueled it 100% diesel for the last couple of fills to clear out the veg oil, hopefully avoiding any issues when I start it after five months parked up). Any tips gratefully received!

[Ares]

I think that veg oil can eat up some rubber hoses so you should think about replacing some of it with some other type of material for hoses.
It would be good if you can start on straight diesel on cold and than switch it on veg mixture,maybe some switch and small reserve tank with diesel.
Also,i heared some people install small heaters in order to prevent oil to create grease.

Plenty of folks do drive it on veg oil so there shouldnt be any problems with it,i would do more freq.check up of engine and all hoses just to be on a safe side with it.
I f you plan not to drive car on some longer period perhaps than definitly inside should be diesel to clean the oil from the engine system.
Hope this helps,keep us posted about your cars beahviour on it cuz im interested too,im driving on veg oil but my car is peugeot 309 1987 year,not TD or anything

[ally406]

I’ve been running mine so far for 22k on waste veg (never had it at a petrol station), and previous to this a 405 1.9TD for 34k. Really no engine issues to report, and the XUD is a tried and tested veggie motor, you shouldn't have any problems.

You might want to replace the injector leakoff pipes as these go brittle with age, more so with veg, and can leak. This costs pennies and is easy to do.

In the very long term, the pump seals might start to fail. This does happen on normal diesel as well, and you should get plenty of warning (leaking fuel). Thankfully you can get bio-diesel compatible replacement seals when the time comes, but in all likelihood you will have long since got rid of the car when this happens.

In the base of the filter housing there is a heat exchanger with a thermostat. This works in cold conditions to stop diesel waxing, but if you modify the thermostat it runs full time, a definite plus for veg and helps prevent the filter from plugging. If you have the housing in peices take the time to re-seal it with some gasket seal, as these housings are notorious for letting in air, and this is even more of a problem on veg oil due to the higher viscosity.

Keep a spare filter and the right hex key in the glove box in case you get caught out (unlikely on SVO, more of an issue for WVO).

You need to shorten the service intervals on veg. In a diesel engine, it is normal for some fuel to blow past the piston rings and contaminate the sump oil. This is fine up to a point with mineral diesel, but with veg not so good. Personally I change the oil every 3k. No big deal as the XUD does not require fancy/expensive oil.

Look in to misfuel. I collect mixed petrol and diesel drained from misfuelled cars from recovery companies. I blend this in with my WVO at 25%. It makes it much thinner and can be run all year round, plus misfuel is free and readily available.

Happy veggie motoring

[straggler]

Thanks for the info.

I don't do many miles and only use new veg oil (80p per litre at Bookers or £1 at Tesco) so I think I should be fine just chucking it in there and maybe thinning it with petrol or white spirit.

That's a great tip about the thermostat on the fuel filter. My old 305 had a pipe from the cooling system running through the fuel filter housing. Pity that's not on the 406.

How much do you pay for the mixed fuel at the recovery places? Are they happy to let you have it (for a few quid in their back pocket, I take it).

I think I read that the HDI engines are not great on veg oil. Is this correct? Are any modern engines ok for veg? If not, I'm gonna start start collecting old Peugeots!

[gumby6371]

Modern diesels with super high pressure pumps and a much finer injector spray are a definite no-no for veg. Many don't even like properly produced bio-diesel.
I hear older mercs are quite good on it but the XUD engine with Bosch fuel pumps will be fine.

If you're parking it up over the winter I'd run a tank of diesel with some injector cleaner through it before putting it to bed.

Personally I put a 'good' dose of forte in every other tank, probably over kill but I don't pay for it as I blag it from work.

Never heard of veg oil attacking seals but if you use thinning agents such as white spirit or petrol or badle made bio-diesel then you do run the risk with them.
I run 1/3 diesel to 2/3 veg in the summer and allow the engine to idle for a while from cold, about 30-60 seconds and you'll hear the hunting stop and it should idle smoothly. You can always increase the idle speed a touch to warm things up a little faster, very easy on the bosch pump.

If you're getting white smoke throw some new glow plugs in as the veg needs plenty of heat to fire and idles much smoother especially from cold.

[straggler]

Thanks for the reply.

Didn't realise it was the thinning agent that attacked the seals. Thought it was the veg oil itself.

Another question - does running on a high percentage of veg oil affect the emmissions gubbins for an MOT?

[StevieboyTD]

Another question - does running on a high percentage of veg oil affect the emmissions gubbins for an MOT?

Yes, it improves them.

[gumby6371]

When I mot'd mine in the summer on a high veg mix the tester had to run the test 4 times to get a reading

If you think about it if hot veg oil gave off noxious gases we'd eat a lot less chips!!

[straggler]

I tried to sell my 406 at the end of last year and ended up getting screwed over by some **** on ebay. I'm glad I kept it now! I only use it six months of the year but with diesel at £1,45 and veg oil at max £1,00 then it's a no brainer. It's so nice to drive long distance (I have the Executive one with all the toys) that I see no reason to get a newer car.

Anyone know of any other 90s cars that are good on veg oil? I'm guessing a 205 with a Bosch fuel system would be good but what about the 106 1.5D? Any other engine/fuel system combinations to look out for?

[ColinCranwell]

I have a 1996 1.9 Executive as well, 254,000 + on the clock, doing about 20,000 miles a year.

What sort of mileage are you getting with the veg oil? I would consider converting if there is money to be saved.
At the moment I am getting between 40-45 mpg.

Regards,
Colin

[gumby6371]

'They' say MPG's drop a little on veg but tbh I haven't noticed any reduction on mine. Getting 37+ round town through the summer with a heavy foot, slightly less now the cold weather has started but no different to diesel in colder weather.

With relatively high mileage I wouldn't want to put pure veg through a possibly worn fuel pump but a 50/50 mix should be fine. You'll still be saving 20p a litre over all depending on your local pump price, do your own maths for the weekly/monthly savings.

20,000 miles a year on 50/50 will pay your road tax and still put some cash back in your pocket

[ally406]

Thanks for the info.

I don't do many miles and only use new veg oil (80p per litre at Bookers or £1 at Tesco) so I think I should be fine just chucking it in there and maybe thinning it with petrol or white spirit.

That's a great tip about the thermostat on the fuel filter. My old 305 had a pipe from the cooling system running through the fuel filter housing. Pity that's not on the 406.

How much do you pay for the mixed fuel at the recovery places? Are they happy to let you have it (for a few quid in their back pocket, I take it).

I think I read that the HDI engines are not great on veg oil. Is this correct? Are any modern engines ok for veg? If not, I'm gonna start start collecting old Peugeots!

The heat exchanger on the 406 is actually a lot better than, fuel comes out at around 40-45 degrees. Take the housing off and you will see it.

Misfuel is completely free and many are glad to be rid of it. Some of it is mostly diesel and I'm certain could go straight in the tank. Avoid using thinners like white spirit, this is not road legal fuel and if HMRC/VOSA were to catch up with you, you could be in big trouble.

Vegetable oil does make some kinds of rubbers go hard and brittle, namely the leakoff pipes on this engine. I would stick on a new set as a matter of course, about £1.50 from a dealer and they'll last you a good long while.

If you find you have starting or idling issues from cold, try a product called Vegi-Boost. The cetane rating of veg is lower than pump diesel, and blending with petrol reduces it further. The result is that combustion starts later in the chamber leading to rough idling and starting from cold, and a reduction in power. A cetane booster goes a long way to counteracting that. Bear in mind that products like Forte etc contain the same active ingredient (2 ethylhexyl nitrate), but in a much lower concentration for a lot more money. This morning was 3 degrees outside and I started the car on 75% WVO, 25% misfuel + cetane booster and it was idling smoothly within 5 seconds.

[straggler]

Thanks for the tip about Vegi Boost. Will definitely give that a go.

I reckon my 406 has got about 3-4 years left before it starts seriously decaying. In that time I'll probably only do about 25,000 miles so running on a high percentage of veg oil shouldn't cause any major nasties, I hope. A friend of mine has a Bookers card so I'll just stock up on veg oil once or twice a year.

By the way, the heated seats on my car don't work. I've checked the fuse in the main fusebox but that's fine. Any ideas?

Was thinking of getting a 306 as a car for my other half. Obviously, I'd look for an XUD with Bosch pump. Did any of the 306 models come with aircon? I've become a big fan of it over the last few years.

[Doggy]

The majority of XUD 306's, (if not all), have a Lucas pump. My bro more or less got away with putting about 50% veg in it. (It didn't actually break, but it seemed to screw up the injection advance system).

It covered a fair few miles on the end of a tow rope, behind one of those really unreliable HDi's you lxuddites hate so much,

[straggler]

Anyone got any suggestions for other cars that are suitable for veg oil?