The Sad Saga of WVOVW

A Waste Vegetable Oil Tragicomedy

WVO Experiment High on Lessons, Low on Miles



CYA Note:  This blog represents only an account of what we did and what happened to us.  This blog is not intended to suggest or demonstrate any steps or methods.  We do not recommend that you do anything mentioned in this blog nor do we recommend that you do anything mentioned anywhere else in the universe. This information is meant to serve only as a case study, as a contribution to the development and use of biofuels for the public good. 


If you wish to convert a car to run on straight vegetable oil or waste vegetable oil, first go to


to learn about the basics, and then you can use this blog to learn about one single WVO experiment that taught us a lot, the hard way.


Divine Intervention?

July 23, 2007              88,941 miles


Since my commute was causing my greatest carbon emissions, I thought it was a no-brainer that I should go for a veggie oil car. I got an email from my buddy Michael with the following heading, and I was sure it was divine intervention.


From: Michael

Subject: Re: 1998 Jetta TDI, Black on Black, 5 speed 55mpg - $8500


The subject line itself sounded too good to be true.  I found out the car had only 89K miles and then the picture of the car that was sent to me by the seller convinced me that God was trying to help with the mission.   He even said the A.C. blew cold.



It sure looked good from this angle! We decided to drive 160 miles to Lorain Ohio to investigate.  This 1997 WV Jetta TDI was the cleanest used car I had ever seen.  We didnít think to check the compression, since this car looked like it had been only driven to church one Sunday a month.  We should definitely have  checked,


or at least checked the compression on the vehicle, but we were destined to learn the hard way.


TDI stands for "Turbo Direct Inject," which means that the fuel is injected directly into the piston prior to compression.  Most WVO websites warn against using a direct injection engine with veggie oil, but a few stalwarts say it can be done with proper preheating. Indirect injection engines, found on older model diesels seem to be more forgiving of viscous veggie oil, which even when heated is six times as viscous as diesel,


We test drove it, and it ran.  It stunk to high heaven, but that's diesel for you.



Carbon Near-Neutrality Made (relatively) Easy

July 24  (89,525 miles) through

November 6, 2007   (95,093 miles)


I bought some brand new low-rolling-resistance tires, Michelin MX4 Energy, and I drove the Jetta on B99 (99% Biodiesel) for over three months. It seemed to work pretty well, though it got nowhere near 55 mpg.  I averaged 40 mpg, on a really good day got up to 42 mpg, even on B99!  The only hassle was the only retail source for B99 was about 30 miles from my home.  I invested in a bunch of five- gallon jugs shown below. (I added "Bio" to the Diesel labels.)

The B99 experiment worked great. I was way closer to carbon neutrality, with very little downside, as B99 sold about 10 cents cheaper than petrodiesel, and the exhaust was way less stinky.    The hundred gallons of storage containers  allowed me to drive to the B99 retailer only  once every two weeks or so.


The exhaust on biodiesel doesn't smell exactly like French friesÖit's more like burning french fry oil, which is almost exactly what it is. 


During this time I had a VW mechanic tell me that under no circumstances should I use biofuel on this car.  I told him that was the only reason I had bought the car, but he just shook his head, "Volkswagen recommends no more than 5% biofuel for their cars, and their engineers know what works for VW."  Reader, you will have to decide if you agree.





Git Under the Hood

Day 1: Saturday, November 10, 2007   12:56 pm

B99 isn't available much past October since it gels when it gets cold, so it was time to switch over to veggie oil.  I secured the waste soybean oil supply from the cafeteria at the high school where I teach for a fuel source, and we had decided  on the Frybrid system which we determined had the best oil heating system. We thought it would take a weekend or two to convert, but a weekend or two turned into a week or two turned into a month or two.


We mainly worked at night, and so you can see the real time investment involved, I have included the times at which many of the photos were taken, so you could follow the process hour by hour.  Generally,  text , dates and times refer to pictures below them.


We started by determining the placement of the tank.  I had seen one tank online installed right at the trunk opening, but we thought that would impede use of the trunk, so we opted for placing it way at the back of the trunk-we decided we wanted a cool fuel filler too, outside of the car to prevent trunk messes.


Our tank placement decision did require that we replace the full size spare with a mini-spare that would fit in the well under the vegoil tank.


To accommodate the vegoil fuel line, We drilled many holes under the back seat cushion, knocked out a bigger hole, filed the edge, then lined the sharp sheet metal edge with heater hose.  The pictures above show the process, but we ultimately ended up having to make the holes much bigger to get both the send and return lines in (see day  15 way below)


4:41 PM                                                                                 5:50 PM





6:25 PM  these are the coolant lines only-we had to these lines out to install the inner aluminum line for the fuel, which you will see below in day 15.




The Frybrid vegoil tank requires a bit of preparation.  We had to drill a few holes to attach the fuel gauge



Following suggestions from others who had done this, we decided to put most of the works including heat exchanger  coil and veggie oil filter right where the original air filter was, so taking out the air filter assembly  was necessary, as summarized below.


11/10/2007 10:32 PM




11/10/2007 10:46 PM



Hurry Up and Wait

Day 2:  Sunday  November 11, 2007    5:39 PM


Got a late start, and immediately got stuck.


We were following an internet blog put up by Jeff of JeffNLisa which can be found at , but we couldn't get the air filter air supply tube to connect  as they suggested, so we were stymied for the night.  We ended up deciding to order a part online and take a break until we got it in the mail.


We couldn't get this to fit on with the existing air hose.


Jeff  at the blog above recommended getting the folds to interlock, but we couldn't do it.

Air Filter and Heat Exchanger

Day 3:  Sunday November 18, 2007   4:06 PM


We had to order the exact tube over the internet, and it took a week to get to us. We bought one colored to match the painted heat exchanger coil.


We cut across the hose at an angle to optimize the placement


but forgot our geometry.  The intersection of a plane and a cylinder is only a circle if the cylinder is perpendicular to the plane.



Re-cut it perpendicular, and it stuck out a bit farther to the left than we wanted.  But it worked!  At the end is an aftermarket cleanable air filter purchased from Murray's Auto.


4:17 PM


Had to remove part of the bracket on the oil heat exchanger coil to get it to fit, and make some adjustments (i.e. smash up) the cavity where the air filter used to go


4:23 PM                                                                                                                     5:26 PM





7:42 PM




The Mounting Plate: Solution to switch placement conundrum.

Day 4:  Wednesday 11/21/2007 9:29 PM


We didn't see a feasible way to mount the fuel switches in the existing engine compartment.  Michael came up with an awesome solution:  a (color coordinated) mounting plate which he fabricated to hold the fuel switches.  This mounted right where the normal engine cover used to be, though this engine was missing its cover.









Fuel system and ready the tank mount

Day 5: Saturday 11/24/2007 8:32 PM


The fuel switches are shown here mounted on the mounting plate




Michael also created a bracket for the vegoil fuel filter assembly, shown here



The vegoil fuel filter fit exactly in an existing circular hole, it is shown below at the left.





9:53 pm



To get the vegoil tank to fit where we wanted it, right behind the back seat, we had to slightly adjust the sheet metal in the trunk.  The circle is the diesel tank gauge assembly, so we had to hammer VERY carefully.




After Midnight

Day 6: Sunday 11/25/2007   12:11 AM


More careful hammering and drilling around the diesel fuel guage assembly. You can see the well for the spare  tire on the left.






11/25/2007 4:53 AM

The engine compartment is starting to shape up.  At the center of the picture , the silver square at upper left is the fuel switch, the square to the lower right in the middle is the fuel return switch.






Aesthetic Improvements and a temp sensor

Day 7: Monday 11/26/2007 9:25 PM




10:25 PM   Assembling the inline coolant temperature sensor.  When the temp sensor gets got enough, it causes the two fuel switches to engage, switching the fuel supply to the veggie oil tank, and the fuel return back to the veggie oil tank.  When the thermo switch is not engaged, the default settings of the switches cause the system to draw from the diesel tank and return fuel to the diesel tank.




Engine Compartment Completion!

Day 8: Tuesday 11/27/2007 2:26 AM


more connections to the heat exchanger, veg fuel filter and diesel filter complete.  The veg fuel filter is hidden in the lower left corner of the picture below.








You can see the location of the veggie oil fuel filter in the picture below, marked with the Frybrid logo.




11/27/2007   5:01 PM

The completed engine compartment:






Prep the tank and its mounting location

Day 9: Saturday 12/1/2007 4:31 PM


With our chosen location for the tank, we lost very little useable space in the trunk, and the backseat was completely unaffected.  Since we were installing a fuel filler cap on the outside of the car, the placement of the tank deep in the trunk was not an inconvenience for filling with veggie oil.


Drilling the holes for the sheet metal screws to hold down the tank.




slight adjustments to the precut hole for the tank heat exchanger






I was trying to check the calibration of the vegoil fuel gauge.  Little did I know that the car's battery which I was using as a power source was depleted (I found out hours later).  That's why the gauge didn't even reach the full level in the lower right picture.  Thus, my calibration check attempt was useless.


12/1/2007 6:57 PM





Wiring and attach the vegoil tank

Day 10: Sunday 12/2/2007  4:21 PM


We inserted all the wiring through a blank "grommet" in the firewall.





The large metal weight used to give the gear shifter some inertia was colliding with one of the installed vegoil hoses, so the hose had to be secured up higher with a zip tie.




electrical connections powering the fuel switches





Sheet metal screws to hold down the tank.  These were very awkward to place and put in.


10:38 PM





Had to cut holes to accommodate the sheet metal screws  in the trunk liner.




The sheet metal screws in place and tank secure.


11:18 PM








Vegoil Fuel filler

Day 11: Monday 12/3/2007 12:25 AM

Took a while to install, but it sure looks sweet.





                                                                                                                                                                 12:49 AM








2:06 AM








Prep for Electrical Work

Day 12:  Tuesday 12/4/2007   2:09 PM


We found it useful to tape the seat back release so we could easily open and

close the seat back.  Otherwise, you need two people to do it (both sides must be released simultaneously)




We wanted to put all the electronics behind the dashboard.  We had to sever the plastic piece which housed the gear shift, otherwise we wouldn't be able to remove it easily. This cut made our job immensely easier, and it wasn't detectable when we put it back together.







12/4/2007  5:01 PM


Wiring Frenzy

Day 13: Wednesday 12/5/2007  3:17 PM

Marking the wires, then marking the wiring diagram helped immensely.






















Here's a close-up of that  circuit diagram.  Michael cleverly color coded the actual wires, by drawing stripes on them with a pen, just as they are here-

a red wire with blue stripes gets connected to "Hot" and a white wire with

black stripes gets connected to the ""Switched"  power.


Vegoil Fuel gauge wired up and installed




12/5/2007  8:34 PM

The dashboard lights buttons and indicators fit well into blanks in the dashboard.



Hosed:  Finish the filler hose, and hose in hose fuel supply and return


Day 14:  Thursday 12/6/2007  8:12 PM

Fuel filler hose, must be diesel proof so expensive!




Cutting aluminum fuel line to length.



Threading hose in hose





This brass fitting allows you to separate the coolant line from the vegoil fuel line after the hose in hose run.






12/6/2007 10:15 PM


One of the hose in hose lines close to final placement.


the view of this line from below the car, going up into the passenger compartment.



We had to bend the seat back slightly to accommodate the hose in hose lines.





12/6/2007 11:03 PM



It is critical not to kink the aluminum line which is within the black radiator hose, so you have to try to avoid sharp angles in the line.  Here Michael is indicating the sharpest turn we had to make with the line, as it went into the tank heater/fuel pickup.


11:08 PM




Day 15  Let's wrap this sucker up!

12/7/2009  1:51 AM


Since you don't want the coolant and the veggie oil to commingle, scratches on the aluminum vegoil supply tube is a bad idea-if they are deep enough, they could cause a leak which could contaminate vegoil with coolant or vice versa.  Luckily, we never seemed to have any problem with that despite the scratches visible in the aluminum line:





Had to increase the size of the hole under the back seat to accommodate the gradual bend of the hose in hoses.




Some cut heater hose dulled the sharp metal edges of the hole.



The view from the trunk of the hoses attaching to the tank pickup heater


The view of the fuel filler from inside the trunk.  Though we assumed the vegoil would run downhill and never leak out from the loose attachment, in the picture below


Sloshing veggie oil caused some to leak out,  so we eventually replaced the above with a diesel proof/leak proof tube adapter shown in the picture below.  The blue hose in this picture is air hose which is needed from the tank to the fuel filler to allow the air to escape when adding fuel.








I was very happy with the tank placement.   The trunk was still very voluminous,


The seat back could be locked in the upright position making the tank invisible. 


The installation is complete except for the purge timing.





We used the fuel dye with biodiesel.  Not a good idea because of the cold weather, but we didnít have any petrodiesel on hand.


When we did the test, we inexplicably got 90 seconds purge time.  We found out later that the purge time was supposed to be less than 10 seconds.  We still don't know why this happened, and it may indicate a bad fuel pump, or an incorrectly done purge test.



We fueled up the next day and had our maiden "voyveg"


It worked!! It even ran quieter and smoother on vegoil than it did on petrodiesel!! What a rush!


The fly in the ointment though was that it took about 20 miles to get hot enough to get the vegoil system to kick on, and even when it was at peak temp, I had to get off the expressway, and rev the engine to get the thermo-switch to activate.


The logical first step was to replace the thermostat, because it might have been stuck open causing low engine temps.  Problem was, WHAT A HASSLE TO CHANGE THE THERMOSTAT ON A VW JETTA!!


12/15/2007 4:12 PM







We finally finished the job at 6:15 pm.  When we tested it, it did not significantly decrease the warm up time.  In other words, it was not due to the thermostat.  But, we eliminated that possibility.


Intermission-Dewatering and Filtration System  November 15-December 15.


Simultaneously with the conversion,  the all important filtration and dewatering project was going on.  I bought the design for a hand pump operated filter and dewatering unit from  Dana Linscott , which can be found at, and gave my environmental science students the task of finding all the components on the internet.  The students found many of the parts we ended up using, and a parent from the community who did filtration work professionally for the auto industry donated many of the parts necessary, and helped us put it all together.  What we ended up with is shown below.




To work it, I simply rolled the plastic 55 gallon drum down to the school's cafeteria where I pumped waste vegetable oil from the fryer into it.  Then I would roll it back to my classroom, pump the oil into the sock filter  (the white circle on the top right) which filtered it down to 10 microns.  The blue barrel has a heater element in it which heats the oil to cause the water to evaporate as well as help the oil flow quicker.  From there it could be pumped through the 5 micron filter (at the front of the unit) and into my tank or storage containers.


To make sure your oil is dewatered enough you can use the "crackle test" very well explained at






Day 16 Thursday Dec 7, 2007



Changing the thermostat didn't greatly improve the 20 mile preheating necessary to switch over to veggie oil, so we thought there might be some air trapped in the heat exchanger.  We used a commercial flush and fill kit and purged the air out of the heat exchanger.  This got messy.  Make sure you have a way to catch the coolant below the car-it must get flushed down a toilet connected to a city sewer in order to be broken down by bacteria.  DON"T PUT IT DOWN THE STORM SEWER OR LEAVE IT IN THE STREET!  It is poisonous to all animals, who are attracted by the sweet smell.



11:00 pm



Because that procedure was so messy, I fabricated a flush and fill drain outlet, by buying a new cap for the coolant reservoir and attaching a hose sized male fitting.  This way, you can drain the coolant right into a hose and into the toilet.



Flushing the air out of the heater core slightly reduced our distance and time for vegoil fuel startup, to about 18 miles.  Still frustrating.


We finally had success in reducing warm up time and distance when we added significantly more thermal insulation everywhere.  We insulated the fuel/coolant lines in the engine compartment and to the vegoil tank. We added  Styrofoam insulation in front of the radiator, and really tried to seal off the engine compartment from incoming air. We then wrapped the temp sensor in a down jacket.  Remember, we're in Michigan in winter, so anywhere cold hits veggie oil, it makes us burn more diesel. We got it down to about  5-7 miles of preheat.  Please note however, that this only worked if I kept the cabin heat off completely for that 5-7 miles. Turning the heat on extended the diesel time by double or triple, since it drained precious heat out of the heater core.






Veggie Oil Honeymoon


December 7, 2007  (95, 093 miles) -Feb 15 2008 (98,009 miles)

The car ran quite well for the next month.   I had to do a bunch of tweaks like tightening the vegoil filter which was leaking, and re-insulating everything several times over.


Disaster strikes 

Thursday Feb 15, 2008


These two connections shown at the bottom of the picture were right above an opening in the bottom of the engine compartment.  The opening was not supposed to be there, but there were two under-engine mud shields that were missing when we bought the car.  I got these later, but it was too late. 


Splattering water and mud soaked the connectors and they corroded, causing a bad connection, but only for the RETURN switch.





We permanently soldered these connections later,  as well as adding two more indicator lights above the veggie fuel gauge (shown below)  to show if the fuel switches were operating, but  by then it was too late.



What happened when the fuel return switch  connection failed: while the veggie fuel supply switch is on, but the return switch is off, flow defaults back to the diesel fuel tank, even when the veg oil supply is working.  This caused about eight gallons of vegetable oil to go into the diesel fuel tank, in the middle of winter.  The vegoil tank was emptying incredibly fast, because it was all going into the diesel tank! 


The car had a horrible time starting on the vegoil/diesel mix, as it was very cold outside.  I have a feeling that this is where we did most if not all of the damage.  I figured it out when my diesel tank fuel level was clearly going up as I quickly ran out of vegoil.


So, we had to drain the vegoil out of the diesel tank..  This was accomplished using an electric pump as shown below.





I had to stand outside in the dead of winter changing out five-gallon containers for three hours as they slowly drained out.  I then put pure diesel into the tank, and drained that out,  added more diesel and drained it one more time.  I kept the vegoil/diesel mixes in marked containers.





This pictures does a pretty good job of summarizing the results of our efforts.  To the left is pure vegetable oil, the second from left is what we pumped out of the tank on the first try.  You can see it looks pretty much like veggie oil, which it was mostly.   The third from left is what I got out the last time I flushed the tank with diesel, and the rightmost container is pure diesel.



1. pure vegoil  2. pumped from tank  3.  last flush,  4. diesel fuel


2/23/2008 6:30 pm

The car seemed to run fine after this episode, and Michael seemed not at all worried about running the freezing cold veggie oil, so I went on my merry way driving the car on veggie oil to and from work, excepting that first 5 miles each way, which was run on diesel fuel (20% biodiesel).


The bumper sticker says "This car runs on waste vegetable oil and Biodiesel" and the license plate is WVO VW




I was greedy to use less diesel though, so we rigged up a pre-heater using some copper tubing and a water heater element.



Consists of copper tubing, an electric water heater thermostat, and a 10 amp, 120 V electric water heater element.


For this pre-heater to work, we had to get the coolant to flow even though the engine was off. We installed a 12 V electric auxiliary centrifugal coolant pump made for Volkswagen cooling systems (which often have weak water pumps anyway) in series with the coolant line near the temperature sensor. The auxiliary pump was powered by a 120 V AC to 12 V DC power supply which we put in parallel with the battery, so the pump could run by AC power when the car was off, or DC when the car was on.


The water heater element could only run on 120 V AC. I plugged the power into a 20 Amp timer, set to turn on an hour or more before I had to drive to work.


When the timer went on, the heating element was energized and the pump pushed coolant through the entire system including engine, veggie oil tank and heater core (not the radiator).  When I got in the car on a frigid winter morning, the engine temp/coolant temp/and fuel in the tank were already up to over 100 degrees F!  This got my  diesel start up time down to only three miles even in winter! It worked like a charm, and I consider this electric pre-heater to be one of the greater successes of our experiment.



This picture shows the inline heater in place, which we of course had to cover with insulation, shown in process in the picture below it.



The following photo stitch-up shows the inline heater in place, with all the components.


temp sensor           inline heater                  thermostat               12 V aux pump                 12 V power supply



Shown below are the switch for the auxiliary  coolant pump, which allowed me to turn the pump on or off at any time (when plugged into an outlet, this switch is bypassed so the coolant is ALWAYS flowing when the pre-heater is on.)   This manual switch also gave me the added bonus of being able to run the heat much longer after a ride, even when the car engine is off, as it drew all the thermal energy off of the entire engine, cooling system, and even the heated fuel tank. (normally you only get the thermal energy that is left in the heater core when you turn off the engine. )  Also visible above the veggie fuel gauge are the two extra indicator lights we added to make sure both fuel switches were on when they were supposed to be.



We connected a 120 V AC power cord to the whole thing, shown in picture below, which was plugged in to an extension cord plugged into a timer so it would run an hour or so before I woke up in the morning. 



Thus, we got the preheat distance down to three miles of running on diesel!!!  The only problem we still had was that the purge timing, being so excessively long, was still using up way too much diesel fuel.


The Bitter End   5/17/08  104,445 miles Ė 5/26/08  105,451 miles


My notes state "Tomorrow I will re-insulate, and reduce purge time"


The 90 second purge time that we had set it at initially was using up gallons of diesel.  I consulted the folks at Frybrid who told me the purge time should be under 10 seconds.  I compromised and set it to 30 seconds.  Something may have been wrong with our lift pump, which was causing the long purge times, but I figured it should still be purged within 30 seconds, over three times longer than it should take.  This may have been a crucial mistake.  Or, the damage may have already been done by running all that cold vegetable oil in February.


On May 20 the car wouldn't start.  Purging the injector pump made it start (after hours of experimenting) but it ran extremely rough after that. 


It started hemorrhaging motor oil, while we were on vacation with it.  It  was having extreme difficulty starting so we couldn't  stop the motor.  We hobbled across lower Michigan filling up a quart of oil every  stop.  In the cars dying gift to us, it got us within range of  range of  AAA plus towing, before WVOVW stopped running completely at around 105,451 miles on May  26 2008.


We found that the motor oil filter was loose, so that may have been the cause of the oil hemorrhage, but we never got it running after that, so we still can't be sure.


The compression test revealed cylinder one at 320 psi, cylinder two at 80 psi, cylinder three at  180 psi, and cylinder four-we couldn't get to because the glow plug was glued in!  The ones we could measure were much lower than they should be.


The glued in glow plug was a hint:  If  we didnít' destroy the engine by ourselves, we may have had some help from the previous owner, but we never tested the compression ahead of time to find out.


I didn't have enough time or cash to take the head off to see what is up.  It might be bad rings, it might be a bad engine, it could be a lot of things.  The lift pump might be bad, the injector pump might be bad, or all of the above.


Additionally, the sock filter that filters diesel fuel prior to the diesel fuel tank may be clogged because of the vegoil to diesel tank catastrophe, so the diesel tank may need to be dropped to clean that out.


We donated the car  to Michigan Technical Academy, a charter school in the Detroit area.  MTA has a fantastic program in which students manufacture biodiesel to fuel the school's buses!  We hope WVOVW will live on in some form or another, and if it doesn't live on, then I sincerely hope WVOWV will rest in peace.









(for now)




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