Posts Tagged ‘engine’

Converting Diesel Engine to Run on French Fry Fuel (used cooking oil)


I wanted to convert my 3.5 ton Mercedes beaut into a French Fry Fuel guzzling monster, so I could just tank up at restaurants and save on costs as I traveled cheaply around Europe in my Caravan, but after much research decided against it cause I was told that the impurities and gunk in the used vegetable post-cooking oil will halve the life of my engine. The engine was awesome and could apparently last up to 2.5 million km, but I felt bad halving all that to save myself some coin and wanted to give greater respect to this long love of mine. Hope she will reach her 2.5 while parked in the Bulgarian mountains waiting for a buyer, while I tour around Asia on a motorbike with sidecarcaravan continuing another chapter in my goofy life traveling.  Below is some correspondence and contacts I compiled while I was researching this. Many people do this and there are many companies providing manufactured components (it requires a second fuel tank. The regular tank starts on diesel, energy heats up second tank of used cooking oil, that heats up enough to raise its viscosity (fluidity, runningness) to spark the fuel (diesels don’t have spark plugs and work on pressure alone). It is a thriving industry. Diesel engines started on peanuts and eventually moved to petrol. Going back to nature is good. Enjoy the read and I hope you find something useful!


I own a 1988 3.5 ton Mercedez 709D diesel truck and I’d like to convert it to WVO (so it runs on French fry fuel – FFF as I like to call it). I live in it and travel around the world ( At around the end of May I plan to arrive and stay in Bulgaria for a few months, and was wondering if it would be possible to send all the necessary hardware there, how much would everything cost, and if you think some Bulgarian car repair shop would be capable of performing the conversion.

Above approach letter to the following:
– doesn’t seem totally related,,


I own a 1988 3.5 ton Mercedez 709D diesel truck (VIN: WDB66906210804372) and I’d like to convert it to WVO (so it runs on French fry fuel – FFF as I like to call it). I reconstructed the interior as a caravan so that I can travel in it around the world ( One WVO specialist stated that the engine of this vehicle is not suitable for such a conversion. Can you confirm whether this is correct?

More people (asking about possible harm to engine):

Mostly Czechs, so sorry the response is Czech below, but very beautiful. The guy is a bicycle rider and said my lifestyle “dycha pohoda” (breathes relax).

key words in subject: konvertovani diesel motor na prirodni olej

Dobry den,

vlastnim 1988 3.5 ton Mercedez 709D diesel nakladak (VIN: WDB66906210804372), registrovany v cechach a chtel bych zkonvertovat motor aby bezelo na kuchynsky olej. Je to mozny? Prej je to mozny s diesel motory ale jeden expert mi rikal ze ne s timhle motorem. Cestuju po svete a chtel bych byt hodnejsi na prirodu.


dekuji za odpoved. Precet jsem to a vsiml jsem slovo “vznetove motory”. Teprve se jenom ucim ale zda se mi ze “znetovy” je “combustion” nebo “ignition” engine, co znamena ze ma “spark”, jako normalny benzinovy motor. Ja jsem myslel ze mam normalny stary diesel motor co nefunguje na princip “spark” (blesk, jiskra – ze je to normalni diesel co pracuje na princip komprese besk jiskra).

Tu technologie o co mluvim neni primichat rostlinny olej, jako nejaky 10%, ale normalne 100% odpadni kuchynsky olej co normalne restaurace vyhodej. Tu technologie ohreje ten olej aby zvysylo viskozity aby komprese normalne funguvalo. Puvodni diesel motor bylo vymysleno aby normalne fungoval na orech olej, a prej vsechny diesel motory fungujou na podobny princip. Staci aby ten olej byl predem dostatecne ohraty. Vyzaduje to dve nadrze: zacit s normalni diesel a prejit na kuchynsky (neni to “biodiesel” co se kupuje) az se ten dalsi nadrz dostatecne ohreje. Je to pomerne jedoduchy technologie, co prej dobre funguje na stary dieselovy motory. Doufam ze se rozumime. Tady je jeden webovy stranky s kym teprve diskutuju: Stale to vice lidi delaji. Jedna nemecka firma je: Zajima mi: je moje motor normalne diesel co nefunguje bez jiskra? Nechapu proc bych to nemohl takhle predelavat.


A diesel engine is a “compression-ignition engine” v. a petrol engine,  which is a “spark-ignition engine.” Any diesel engine can be converted  – how complex and expensive the conversion is does depend on the  engine in question, and some of the new engines are more expensive to  convert, but none are impossible. I’ll let Ed explain why there are some in the industry who are anti- biofuels.

sorry I meant “combustion” and not “compression”. My truck takes regular diesel fuel, and is 1988, so an older one. One of the conversion companies suggested a newer model – a Mercedes Sprinter as opposed to the Mercedes Vario that I have.

I can understand why some in the industry would be against this in general.

Here is an excerpt from the pdf file Mercedes sent me (translated from Czech):

“biofuel… converted to corresponding mixture of methylester oily acids (FAME)… Chemically unchanged vegetable oils (such as rape seed oil, sunflower..) must NOT be used in Mercedez Benz combustion engines. The use of chemically unchanged vegetable oil can in a short time damage such an engine, for the following main reasons: formation of carbon on the spray nozzles; in the piston ring grooves; in the oil channels and so on – due because of high viscosity; high boiling point (incomplete preparation of mixture); partial decomposition of carbon (during overheating).

Anyway, I’m skeptical, but also want to be careful and don’t want to damage the engine. I’ll do some more research, but if there’s any chance, I definitely want to move forward with this.

Ed doesn’t seem to be responding to my emails.


some of the conversion companies (after studying my model with vin number) and the manufacturer itself (Mercedes) are saying that I have a “combustion” diesel engine which is not suitable for vegetable oil and have listed some reasons (which I can forward to you if you like). My diesel engine is 1988, so an older model. Perhaps they are thinking about SVO and not WVO? I wouldn’t want to damage the engine. What is your take on this? I’d really like to convert, but I now live in my truck and definitely wouldn’t want to damage the engine.


I have a VIN number for the Mercedes engine, based on which the manufacturer and several conversion companies said that this engine was not suitable for such a conversion. I can send you the VIN number if you like.

The conversion companies which said the engine was not suitable for conversion, mostly after getting the VIN number from me (some just based on the data I originally submitted at the bottom of this email), are the following:

– – I believe a German based company, same as Mercedes


Will be glad to compensate you for your time and efforts.

I am not sure that I am familiar with the particular engine in your truck. Do you have a shop manual for it? Do you know what model engine it is? I don’t know of any manufacturer that will advise their diesel engines be run on SVO or WVO except for the new stationary engines by MAN and CAT.  Which conversion companies suggested that it should not be converted?

I do not supply conversion parts.

some conversion companies and the manufacturer (Mercedes) itself say that I have a “combustion” engine (although it takes regular diesel) and say that my model should not use vegetable oil (perhaps they were thinking SVO and not WVO). Others are saying it is definitely possible. I can send you some money by PayPal for your consultation but I definitely want to convert to WVO, while I definitely do not want to damage my engine. Any help or suggestions would be appreciated.


Hi I have been traveling and was at a meeting and presenting a submission yesterday for government for a feed-in tariff program for renewable energy. Ignore the stuff about not using vegoil in your Mercedes, they are sending you the party line and it does NOT apply to a two-tank heated approach which is what we do and we do it to AVOID the issues mentioned. Your engine is in fact much MORE suitable than a newer common rail, like a Sprinter has and you will not have any problems.

Hi Edward,

that is what I thought. I any case I will research some more, because it is my house and without it, well, I’m poopoo, so must be careful. Definitely look forward to materialising this. If possible please answer some of the other questions I sent you before. Have the cash in bank and would like to have all the parts inBulgariaaround the beginning of June.


thank you for the inquiry and your interest in ATG products. Meanwhile there are over 8.000 vehicles/motors worldwide equipped with our veg oil systems. Please find attached our current price list for ATG Vegetable Oil Kits. If you like to order we’ll send you a proforma invoice with shipment costs in advance. The sipping costs are depending on the size of the fuel tank. For a Mercedes 709D we recommend the kit P121012 + EK1210 fuel pump (not on price list, costs 68 EURO) + tank up to your choice. If you have any further questions please do not hesitate to contact us.

Hi Franz,

sounds good. Perhaps I could get a custom-made or used tank inBulgaria. Will research further. In the meantime, some conversion companies, including Mercedes itself, are saying that my engine is not suitable for such a conversion. Please tell me your opinion concerning this. I live in the truck and it would be catastrophic for me if something happened to the engine. I spent three years converting the truck into a caravan, and I run my business through an internet connection while I live in it.


You will want to purchase a manual for your engine/truck no matter what. Having one is usually a very good idea when long distance travelling and can easily save the cost of the manual with one use. If you plan to install your own conversion it is mandatory. They are often available on CD which is best for our purposes. If you cannot find a manual for your engine/truck I would not advise converting it.

all the companies offering conversion kits say it will come with instructions and a manual etc., but I will probably find it worthwhile to get more information etc. What do you suggest? I’d also like to research if it is possible with my truck. Perhaps some Mercedes forums or something. Know of anything you could suggest?


Hi Franz,

I think your offer is the best and I will go with yours, but I need some time to save up the money. In the meantime, one issue occurred to me: I gather the heater runs on 12V? My truck runs on 24V, but I have a separate 12V solar system for my mobile office etc. Also I think the truck’s alternator is rather week (it may even be kaput at the moment). I was thinking that perhaps I could buy a better alternator, and then a 24 to 12V converter and figure out some combined system to heat up the grease. If I use solar and heat it up before I start the truck, I gather I can use the grease right away and not start with diesel?

Thank you, and looking forward to eventually realising this conversion.


oh yah, and I wanted to ask you if you know anything about WVO or SVO, where WVO (what I’m interested in) is converting my old diesel truck so that it runs on used cooking oil. There’s a second tank which heats up to the proper viscosity, and you only switch to/from the diesel tank when starting or stopping.

Want to research it more but many seemingly smarter about cars dudes I’ve mentioned this to said I will trash and get about half out of my engine if I go this route. The engine has already gone 600k and sounds fantastic. Wouldn’t wanna hurt my truck’s heart. k


Haven’t done any bio-diesel research at all, since none of our cars are diesel. I have seen it a couple times, one thing is that goop gets everywhere – imagine heating up a bucket of grease in your trunk and the assorted slops, drips, leaks and such. I had a tour guide with that set up stop by to get a boat so I checked it out but it was messy as hell, all over his stuff. Maybe he was a slob, but there was a lot of hoses and you have to pour the stuff in each time and anyway…he liked it but now idea if it was WVO or SVO.

Yah, I think SVO is when you make your own biodiesel, which can be sloppy and time consuming. WVO is when you have a second tank which heats up the used stuff to the proper viscosity. Perhaps there is some filtration required but not sure. A fascinating subject and will have to research it thoroughly once I have the cash to convert (about 1500 Euro). Cheaper in NA though I think (found a good company if you need). later

Electrical Hookup in Caravan – DIY
Internet Connection While Traveling
Witchburning in the Czech Republic – with Led Zepelin’s “Stairway to Heaven” at half speed – scary shit!
Wherever I lay my hat, or park my truck, I shall KEEP TRAVELING