VEG OIL Concentrations in OM603

[d215yq]

Hi all,

Not looking for advice to not do it, more on the best mix to have a minimal risk of problems. I have an old OM603 that is used in high temps (minimum 15 degrees) and am currently doing 1,000 miles per month all long journeys so the fuel is going through it pretty quick and the engine is running cold about 0.1% of the time.

Now in the past I've used free old diesel, 10yr old (but fresh engine oil) and veg oil in it but only up to 20% (50% to get it through emission in MOT but only just for that and then fill with diesel so basically always 80% pump diesel). It always runs smoother with the 20% mix though i think power may be down a bit, and mpg remains the same.

Now as Corona virus hit I thought (wrongly) that petrol stations may close but that I could head to the mountains on my own as that is not going to spread any virus.... so I filled the tank with diesel and bought 140L of sunflower oil so I could enjoy the socially distanced lockdown goign to the mountains every other day for 3 months! Now obviously the opposite happened and I was not allowed to drive for 9 weeks and the petrol stations stayed open and the pump price even went lower than what I paid for the sunflower oil

But never mind, I've got 120L of it still and have further inherited 30L of old sunflower oil and 20L old olive oil in the old house I've bought. Now I don't do that much cooking and don't really want this stuff hanging around nor to use it in winter when it gets colder so what's the highest ratio I can go to in an OM603 to get rid of it quickly? I'm thinking I'd rather do 50/50 when the car is used and it stays warm and get rid of it and then switch to 100% pump diesel in November when the temps will be colder and car will get used less...anyone with experience with this sort of thing done somethign similar?

 

[LostKiwi]

 

[Doug1234]

You can use it at 100% , only thing that will alter that is the weather temperature when you first start the engine up from cold.
So you can add say 5% petrol or 15% diesel to thin it a bit ( you always need more diesel as a percentage to get the same thinning effect petrol gives) this will help it start better on colder mornings.

My w124 ran neat veg oil in the summer in UK and winter I would go up to 15% petrol maximum. Once it got really cold then I would go 50/50 veg diesel.
I used the car everyday so it had at least two cold starts and one with a semi warm engine to put up with in the winter months and apart from being a bit lumpy for a few seconds after starting it was happy enough with it.
The saloon w124 has the fuel tank behind the rear seat inside the car so it holds any heat well overnight.
The om603 is one of the best engines for running vegetable oil in so really only getting started in the mornings in really cold temperatures is the limiting factor , you may get a bit of grey smoke or even a good cloud of it but its normal when running veg.

 

[John Laidlaw]

Not sure on the mix, sorry just the usual heads up on fuel hoses and pump seals....

 

[brianbrian]

Messy keep changing filters, the fuel tank filter is really messy, not worth the trouble.

 

[d215yq]

Thanks for the replies, I've changed the filters (except the tank one) already and the car has run fine like this on and off for 3 years - worst case i could change the prefilter and main one in a few minutes - the main one I think is due anyway as I last did it 50k miles ago.. - I used to add 20% veg oil to save money but little point now as the diesel price is so low but as I've got stuff to use up so might as well. Probably not for everyone but there's many stories as per Doug's where these have been run for years on up to 100% with no modification and no problems. There's no need for me to go 100% but will do 50/50 mix for the next two months and then go back to 100% pump diesel for winter

 

[Botus]

no advice not to... but I few pointers

mate doing lots of miles did this, but noticed it seemed to bring premature failure of his glow plugs

second one was my brother who was doing this lots and trashed 3 engines. it causes the rings to gum up and the pistons melt. one was good merc, he doesn't do it at all anymore.... and having been the biggest proponent I ever met no longer talks about it

I would at most do one fill with real stuff then one mix...

of course all the stuff about mould growth and rust where you don't need it go as a given.... on a fossil with a old school pump give it at go at 50 50, every other fill.... if its is a common rail high pressure thing, 10% to 20% every other fill but expect your wallet to get emptied

 

[Doug1234]

Tank strainer , if you ever have to remove it then either replace or just remove the mesh from it.
Mould growth , use Starton starbrite diesel enzyme treatment ... this one kills moulds and algae by basically dissolving them to allow them to pass through filters and be burnt off and it is also a cetane booster containing 2ehn...other biocides kill growth but leave blocked filters.
If you constantly run veg then use a wallpaper steamer every 4 months or so and let the engine breathe in the steam and this decarbonises the engine and free’s up piston rings that are gummed with veg residue, about 6 litres of water over course of an hour or more usually does the job.

 

[matthew k]

I ran a Vectra Di on veg oil for a year. Used to add 5-10% petrol to thin it. Never had a problem, it was harder to start, but ran fine. Seemed to thicken the engine oil though, and it ran quieter on it.

 

[Tony Dyson]

Thanks for the replies, I've changed the filters (except the tank one) already and the car has run fine like this on and off for 3 years - worst case i could change the prefilter and main one in a few minutes - the main one I think is due anyway as I last did it 50k miles ago.. - I used to add 20% veg oil to save money but little point now as the diesel price is so low but as I've got stuff to use up so might as well. Probably not for everyone but there's many stories as per Doug's where these have been run for years on up to 100% with no modification and no problems. There's no need for me to go 100% but will do 50/50 mix for the next two months and then go back to 100% pump diesel for winter

Question, Have you ever just poured a 50/50 sample mix of your Veg oil and Diesel in a glass flask to see if there is any natural separation of the different fluids into layers? Is your belief that you're consuming a homogenised mix based on an assumption where in fact you're actually burning alternate layers of your tank contents?

 

[Doug1234]

If you dump veg oil in the tank then you will be running nearly neat veg until it gets mixed in with the diesel, this does not take long with the om603 / om606 as they both circulate from tank to engine and back quite quickly.
If you remove even one leak off pipe from an injector at tick over at least a litre a minute will pour out.
Once mixed they do not separate.

 

[Craiglxviii]

A warning, SVO may need dewatering before use.

 

[d215yq]

Question, Have you ever just poured a 50/50 sample mix of your Veg oil and Diesel in a glass flask to see if there is any natural separation of the different fluids into layers? Is your belief that you're consuming a homogenised mix based on an assumption where in fact you're actually burning alternate layers of your tank contents?

That could well be the case...I haven't really ever thought of it at all really.... other than I like to receycle things and save money and have heard these engines take anything, particualrly if used on long journeys in a warm climate, so have just thrown motor oil, old sunflower oil, free diesel of unknown source etc in it keeping the pump diesel percentage as high as possible. As that was all fine I go up to 20% sunflower oil in France/UK when the prices were high but now in Spain it's 0,95c/litre I don't do that any more...

But in lockdown I wanted to stay mobile so extra fuel was the priority and I now need to get rid of it. To put it into perspective it's got 300k + miles (odometer broken so probably a lot more), every panel is damaged and has lacquer peel, half the interior is falling to pieces and the rest is covered in plaster dust, the boot is full of earth and cement dust as I'm rebuilding a house at the moment, the prop shaft vibrates at 50-60mph, the engine vibrates at 2100-2300 revs...I could go on, if it's a decent punt it'll soldier on after using up my veg oil why not, it's not exactly goign to be a future classic... I only keep it because after initial problems were fixed when I bought it over the last 4 years it has never cost more than 500€ in total annual service/maintenance/consumables despite doing 20k miles pa and has never failed an MOT and does 50mpg so why go out of my way to replace it with something that will almost certainly have higher runnign costs? And using veg oil can make the running costs even lower!

 

[Doug1234]

You will look back on this w124 in years to come as the best car you have ever owned 100% guaranteed.

 

[d215yq]

You will look back on this w124 in years to come as the best car you have ever owned 100% guaranteed.

Strangely I think i already do, I have a company car coming in January, I can pick any top of the range new Ford and it will get replaced every 6 months. I've test driven a few and while it will be nice to have a proper stereo, a/c that works and some leather and 0-60 in 8s I can't get so excited about doing next year's 3x 2000 mile trips to UK through france in it. Lack of driver involvement and computers controlling everything or maybe just too "easy a drive" without having to perfect smooth starts and gear changes means less of an experience in my book.

I also maintain the W124 and know (sort of) how it works, remember changign the brakes, bodging the leaking washer resercoir with araldite, cutting my hands replacing all the fuse hoses super quick before it lost too much diesel, etc etc.

The new car will be insured on the company with 0 excess but I'll have to report parking dents (very frequent here as people touch park) etc - it will be a new world and more hassle on this front. Atleast with the building works I have an excuse to keep the W124 as that can collect all the dirty cement/sand bags and green waste on my land etc which I can't put in the new car...it. That said I wouldn't sell it anyway for the few hundred quid it's worth. I think I will eventually (once the house is all done in a year or so) bit by bit make it mechanically perfect, learning more about mechaincs along the way and replace the interior with a nice light colour leather one so it's nice to be in and nice to drive and just leave the boot and bodywork all tatty so it can still retain it's "utilitarian" purpose.