Can used, filtered cooking oil be used in a diesel engine just straight?

Question

Basically im wondering if i could go down to the mcdonalds and snag some of their used french fry oil, put it through a coffee filter, and shove it in my car and have it run on that. Im noticing that gass prises arre rising like crazy and there are no biodisel vendors close enough to my house that i could use that. Thanks for the answers!

Answer 1

So far I've found four issues with waste vegetable oil.

#1 Viscosity.  As you know, all vegetable oil is thicker than diesel fuel, and that's more than some pumps and injection systems can handle.  So you are likely to have problems cold-starting the engine or running in cold weather, and may even break pumps or injectors.

#2 Particulate.  Junk in the oil could clog injectors or filters, or create engine hotspots.  You MUST filter the oil more fine than the inline fuel filter on your vehicle.  If you pre-filter to 25 microns, but your vehicle's fuel filter traps to 10 microns, your vehicle's filter will quickly become choked with particles between 10 and 25 microns.

#3 Acidity.  Used fry oil tends to have a funny pH, and this may corrode the fuel tank, lines, filters, pumps and injectors.

#4 Water content.  Water in diesel = bad.  Again, corrosion of fuel system and annoying cleanout of filters.

You can process the fuel to handle problems #2 #3 and #4.  However by the time you deal with #3 and #4, you've done most of the work of brewing biodiesel (which solves #1 as well).  So you might as well just do that!

Of course, if you run a 2-tank system where you start and shut down on (bio?) diesel and run SVO inbetween, you might get away with acidity and water content, as the fuel is purged from the system before you shut down.

Answer 2

I know gas is ridiculous! I put $10 in and got about 3 gallons! Never put anything other than what's required in your vehicle. What I've been doing to save money is check a website to see where in my area is the best deal. Here's what works for me:

http://gasprices.mapquest.com/index.jsp?...

1&ncid=MPQMAP00170000000008

Good luck!!

Answer 3

There's lots of different answers posted here and I'm not sure any of these people actually have diesels so let me tell you as I have 4 of them and use vegetable oil in all of them.

There are 3 ways to run veggie.  All include making the veggie oil the same viscosity as diesel.

1 - process it to make biodiesel, by removing the glycerin by adding methanol and either KOH or NaOH.

2 - heat it with your cars own cooling system which brings it to 180 degrees

3 - Thin it with Kerosene or gasoline

All three work.

If you have an older diesel (1980's In-Direct Injection) you can almost run it straight, after you filter it to 10 microns.  I run it straight in 2 of mine.  After the engine warms up you can't notice a difference.  Don't use it straight if it is going to get cold at night as it will get thick and congeal in the fuel lines.  But since we are going into summer it isn't a problem.

I also have 2 newer diesels that have direct injection, one is a VW TDI.  These require a mix.  You can "cut" the filtered oil with kerosene or a small amount of gasoline.  Never run straight gasoline in a diesel as it doesn't properly lubricate the injection pump.

Don't use McDonalds oil, as they use the cheapest c**p they can get.  Go to Chinese restaurants as they usually change their oil often and it is almost always non-hydrogenated.

My suggestion is find a source of oil, filter it, and then start adding small quantities to an already full diesel tank, then every day or so, add more until you are comfortable with how it starts and find a mix percentage that works for you.

My 1986 Ford F250 has 2 tanks.  1 I have pure biodiesel in, and use this tank to start it up in the morning.  After 2 minutes I switch to the pure veggie.  When I am a mile from my destination I switch back to biodiesel to "flush" the veggie from the lines for the next start.

The old Mercedes 300d takes it straight all the time and never had any problems.

If you plan on not using the car for a few days, fill the tank with diesel and flush the system before you park it as some people have noticed the veggie oil making their valves stick if it sits for too long.

Anyone who tells you different has never used it and doesn't know what they are talking about.

last thing.  Make sure your source of oil has no water in it, and always let it settle for a few days and never pour the last inch or so in your car as this is where the water and sediment is.  Also carry a fuel filter with you in the trunk with a wrench to replace it.  Never had mine clog completely to where I couldn't drive it, but plenty of others have.  Good Luck!

Answer 4

When Rudolf Diesel originally designed the high-compression engine, he had in mind the use of vegetable oil for its operation. Sateen (paper) filters wouldn't be effective enough. The sediments should be allowed to settle to the bottom of the storage container, and the clean fuel on top is to then be siphoned off. At the time of the diesel engine's design, The prominent seed-oil crop was hemp.

Answer 5

No...unless you want the extra expense of having your diesel engine overhauled!! I don't know the exacts of how they combine biodiesels together but common sense would tell me that it's more strenuous than just simply filtering through a coffee filter and add couple scoups of diesel...and on your way!! Wish it were though....sucks that the has prices are out of sight!!!! Ever wonder why fuel costs go extreme and salaries don't.....hmmm!!

Answer 6

depends on your engine and set up...some people work it out so they have minimal work with the oil - like you are talking about. however if you set it up this wway you need 2 tanks cause the car has to start on gas first and then you switch it over...

Answer 7

It depends on the configuration of the engine. Usually all you really need to do is filter the cooking oil and you also need to put the cooking oil in a container that can feed the engine via gravity because finding a fuel pump that can pump a very dense liquid such as cooking oil is very difficult.

Answer 8

They tested this on Mythbusters and the diesel engine started and ran normally.  They drove the vehicle and didn't notice any difference than if you would have used diesel except for a slight drop in mpg, but why does fuel economy matter when the fuel is free?  I think that as long as you filter out all the large particles and have only pure oil, you should be able to use it.  I don't know if the oil will have any long term effects on any part of your vehicle because the Mythbusters only ran it for a couple minutes, so do it at your own risk.  But with skyrocketing fuel prices, I would try it.  Any damage that the oil causes will probaby cost less than if you would have used diesel fuel.  Hope this helps. :-)

Answer 9

No filtered used cooking oil is not an approved fuel and could clog your engine.

There are websites that will help you turn that cooking oil into bio diesel.

WARNING

If you do this you would not want to exceed 20% bio diesel to 80% regular diesel.

It could clog or damage your engine especially if it is older.

Many of the websites and books I have read on this issue state that you would wish to start using a smaller percentage at first then go to 20% in an older engine.

Could you use a higher percentage sure but it can cause problems.

Especially during the winter time.

Bio diesel has a lower gel point so it will not flow as well in winter.

Answer 10

I asked this question awhile ago. You have to make a few conversions to your car before you can use straight vegetable oil. The converted cars are called frybrids or greasiels-google those for directions because I don't know exactly how to convert the car.

Answer 11

Well...the answer is yes and no...

Can you get some used oil, filter it through a coffee filter, and run it in a diesel engine?  Yes, you can.  It is not something that I'd recommend though.

On a high level...petroleum diesel is a very dirty fuel anyway.  If you pass used oil through a few good paper filters, it will get most of the sediment out.  The fuel filter should get the rest.  However, there are two issues with doing this.  First, used oil can be mixed with water.  If the oil isn't dried somehow, you can get water in your tank and engine.  Second, cold cooking oil supposedly make it difficult to start the engine (I believe all after market veggie oil kits heat the oil before it gets to the engine).  Third, veggie oil gets gummy and will eventually s***w up your engine over time if it is just used straight in the engine.

If you have a diesel, you can do one of a couple things.

First, you can get a kit that will allow you to safely burn veggie oil in your diesel (see http://greasecar.com/).  The plus with these kits is that it requires little prep work of the oil.  The downfall is that the car must be started and stopped on petroleum diesel.

Second, you can make your own biodiesel.  The plus is that it is fairly easy to make, the main byproduct is a safe product (glycerine if I recall correctly...sorry I don't make my own fuel).  The problem with making biodiesel is space.  The equipment, chemicals, and tanks take up room.  The other downfall is that biodiesel is a great solvent for dirt.  It tends to pick up the dirt from the pertoleum diesel and clogs up the fuel filter at first.  You can check out a few websites on making biodiesel....try http://biodieselcommunity.org/ or http://journeytoforever.org/biodiesel_ma...

Cheers...

Answer 12

In needs considerably more filtering that that, but it can be used in a diesel engine once it's filtered enough.

Answer 13

sure.  Why not?

Answer 14

It's not too expensive to set up a filtering system for the grease and you probably do it.  However, you can't just pour it into your fuel tank.  You have to have a separate tank and fuel line for the grease.  A diesel engine can only be started and warmed up on diesel fuel.  After it gets warmed up it can then switch to the grease.

There are kits on the net to switch your car over.  the main problem is finding the grease.  A lot of restaurants already have somebody or some company picking up their old grease.

Answer 15

I saw them do it on Myth Busters on Discovery Channel.  Their diesel car ran fine without a hiccup.