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· Registered
2 Posts
Biodiesel use

I just asked my local dealer about the use of biodiesel in VW TDI engines. He sent me a PDF file from VW with the following summary.
In summary:
1. Volkswagen recommends the use of standard
diesel fuel or commercially supplied biodiesel
blends of no more than five percent (“B5â€￾) biodiesel.
2. Never use any fuel, whether diesel, B5 biodiesel, or
otherwise, that fails to meet the latest petroleum
industry specifications or that is not purchased
from a commercial retail diesel pump. If you are
unable to determine whether a particular fuel
blend is B5 biodiesel that meets the latest biodiesel
industry specifications, ask your service station for
more information.
3. Never use any fuel for which the contents cannot
be identified.

· Registered
29 Posts
I looked at a house last fall that had a couple of dozen big white plastic drums of biodiesel and used cooking oil stored next to the garage. The daughter had an A4 Jetta TDI and traded it on one of the first '10s. The new car was in the garage requiring a huge repair that was apparently not in the budget. The real estate agent didn't know the particulars, but it was enough proof for me that the pdf that CVML98 mentioned is the real deal.

· Registered
3 Posts
I just purchased my 2010 Jetta Sportwagen TDI this week. I did quite a bit of research on using biodiesel with it before purchase but since the post-injection DPF filters are so new (only out since 2009) there's not much "real-life" information out there. Basically, VW warranties the engine for ASTM-certified B5. When I contacted biodiesel wholesalers in my area they all encouraged me to use up to a B20 blend and I've found some sources online that seem to think that would be OK but it's a risk as the use of biodiesel with the DPF system can deplete oil, clog the filter and reduce efficiency. I've sourced commercial B5 in my area and intend to use that and have my oil and filter checked more frequently. I may use up to a B20 blend in the future but am taking baby steps right now since I really can't afford to replace the engine if it goes. Here are some links that might help you decide for yourself:

Diesel particulate filter DPF and Adblue fluid FAQ
Understanding the Post-Injection Problem
VW world’s 1st automaker to warrant B5 biodiesel
2009, 2010, and 2011 VW Jetta Sportwagen (Golf wagon) TDI buying checklist and FAQ (check out the Biodiesel section)

Let me know if you find other info. I really want to use biodiesel but I don't want to risk recking brand new car. :/

· Registered
KJ & WK CRDs - between VWs right now
27 Posts
Biodiesel use - after years of use...

I've been using Biodiesel for several years in a variety of Diesels. Prior to this I blended filtered WVO, have even used used motor oil... I've also learned that filters can clog pretty quick... :)

Problem you'll typically encounter with either is trouble with seals dissolving with both WVO and BioDiesel. Depending on how well your BioDiesel is processed will determine if you will have troubles that way. I've had to replace a few o-rings and the high pressure seals in my '91 300D. Other Diesels like a 1.6L Caddy I had to do nothing. GM 6.2 and 6.5 Diesels required replacing anything rubber in the system and an aux pump... ugly messes.

THEN ON MY TDI... (which is sitting dead in my shop waiting for parts maybe because of the 1st tank of BioDiesel)

on my 2003 Jetta TDI on the first full tank of BioDiesel I got error codes, hammering sound from my IP and loss of power... I pulled the injectors, two were bad... replaced the filter... cleared the code... a couple days later, hammering started, code P0252 reappeared. Talked to the Diesel shop, we determined a Diesel Purge might help it did... for about a day... then it started again... DP, one day... DP, 1/2 a mile... Got the triangle tool, pulled the pump apart, cleaned the Fuel Metering stuff... worked great for about 15 miles... then hammering in the IP, loss of power (not revs though) and P0252 and P0251 (ah ha! the metering code!)

Here's picture of the insides for those of you that have no courage... or don't live life on the edge: (if you're faint of heart, don't look... if you like this sort of things will be happy to share the links to the inside of my Nikon D300)

Bottom line, I can not say with certainty that this would have happened had I not had a full, 100% BioDiesel tank or not... But then again, this TDI will not see BioDiesel again... no point at 40-50mpg... will use it in my other Diesels.
My 300D really lost power on that batch of BioDiesel so I suspect it was bad, I also had to change the filters on it. This was the first batch from a new co-op/friend... perhaps my last. ;)

Anyway, watch for rubber parts dissolving, loss of power, lower fuel economy, but less costs (typically), nicer exhaust smell and the feeling like you're getting over on the system... i.e. no fuel taxes! We like to think it's free, but one spends a lot of time lugging cubies and buckets around, my shop floor is gross...

Oh, BTW, that metering control part... it retails for about $1100 if you buy it from an injection shop, their cost is $500. The dealer doesn't sell it, only the pump, retail prices is $1402.

I'm planning on buying a rebuilt pump from http://DieselVW.com unless one of you tells me I shouldn't. I think I'm going to spend the extra $100 for the full Bosch pump... the aftermarket part pump is $700 minus $300 core = $400.

I've gone as far as I can with this without replacing the IP... Christmas break project...

BioDiesel usually results in lower power and mileage... on my '91 300D in town mileage is typically 28-30mpg,
with BD it can be as low as 23, typically 26 or so... and the car can be quite gutless. Smells better though.

The exhaust on the TDI was much nicer with BioDiesel.

I'm building an '83 J10 Stepside with a Scout Diesel drivetrain, ran an SD33 with 100% BioDiesel for over a year, NO PROBLEMS whatsoever... my '91 300D has been using it for years with mileage loss and power loss but no other issues... except for an o-ring in the fuel heater and the high pressure seals, which I can do in the car in very little time, again, faint of heart, don't look: http://johnmeister.com/DieselBenz/TECH/124-series/Pressure-Valve-Seal-Replacement-2010/ALL.html

· Premium Member
22 Posts
I make bio for sale and my own use. I also make bio and store for a 2001 Golf owner that supplies his own feedstock. There have been no problems running 100% bio in close to 3 years. First thing he did was fit an after market fuel pre-filter (before the VW OEM filter) with a glass sight bowl using multi fuel hoses. Good quality fuel will not cause any problems in these cars.
DieselJohn, I suspect poor fuel through poor conversion or unsuitable feed stock for the ambient temperatures you were experiencing.

· Premium Member
61 Posts
OP read your manual please and follow it in regards to BD. Does your vehicle have a DPF? If so, don't use anything greater than B5. If you have a PD engine and no DPF, I would still be careful, monitor and limit the percentage of BD but personally in the, PD no DPF, I have strayed to the B50 mark during the summer with some performance issues and so backed it down some. If you do not have a PD (I don't know about the CR engine itself and BD) and also no DPF, but have vitron fuel line, do what you wish.

The folks successfully running B100 here are in older TDIs

· Registered
16 Posts
I ran B100 almost exclusively in my 03 Jetta for about 75K miles with no problems at all. (Well, almost, it gelled on me once when a cold front sneaked up on me.) No noticeable decline in power or efficiency. Sounds like the guy with the trashed Audi, if it was caused by the fuel, was a home-brewer and could have screwed up a batch. I got mine from Houston Biodiesel. Their fuel came from the refineries in the Houston area. At the time there were several refineries producing biodiesel in the area. And it was generally about $0.50 less per gallon than petro-diesel, and still is.
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