Just a quick question to see if anyone runs biodiesel in a PD engine and what if any, problems have occurred?
I've heard bio gunks up the nozzles and causes bad running? And vw only recommends a small amount be used.
Thanks in advance for the help
I have a 2005 VW Passat TDI I converted with a Greasecar kit several years ago when the car had only 25K miles on it. Currently we have 125,00 and have had some issues mainly due to operator error. Full purging the engine in Rocky Mountain weather is critical. My setup had the valves ~2.3 ft from the injection pump so it takes a while to purge. As such Dumb a$$ me forgot to purge before we got to the hotel (on a ski trip) and let it idle for 5 or so minutes. The engine doesn't use much fuel at idle so I think the system wasn't purged. Next morning VERY hard to start, but finally did. That happened twice.
Shorter lines and perhaps a timer to automatically shut down the system is a really good idea.
I had some significant blowby for several months and treated the engine with a GM product to unstick rings (apparently a problem with some Caddys) when I changed out the turbo. Took out glow plugs squirted 100 mL of stuff, rotated the engine, let it soak, and repeated . I put a cloth over the exhaust manifold and started w/o the turbo. Good thinking as chunks of crap came out. I also treated the fuel for 6 months and the blowby seemed to abate. Other than that the car runs strong.
The oil/balance shaft chain issue is still a big worry though. Just bought a kit from Bora to eliminate the balance shaft.
WVO has also gotten harder to obtain.
I use water-washed and dried biodiesel in my 05 PD Caddy, 100% in warm weather, about 50% in (S. Australian ) winter where freezes overnight occasionally. Seeing what I refine out of used oil I wouldn't be caught dead using uncatalysed veg oil. Runs very clean. Only one problem at first internal fuel pump filter gunked in cold weather. This vehicle does NOT have a diesel particulate filter which can initiate a clean-out cycle in which fuel is injected on exhaust stroke leading to sump oil contamination from unburnt bio off cylinder walls.
We bought a brand new Jetta TDI PD (BEW) in 2005 and have used various blends of biodiesel up to B100, averaging close to B50. We now have just over 250K miles on it. Our fuel mileage has averaged a bit over 40mpg with mixed highway and back roads in the NC mountains. It still has the original clutch and front brakes (!) -- back brakes and rotors were finally changed last month. I have needed to repair or replace a lot of "little" things, like the ventilation fan, door lock modules, headliner, alternator pulley, etc., and I also needed the "dog collar" mod when the upper intercooler hose sheared off. When diesel changed to ULSD in 2008, we had fuel misting around the injector seals after we ran straight diesel for a couple of tanks, and our lift pump also failed at that time. I read in a tdiclub forum that bio tends to swell injector seals, while ULSD shrinks them. For us the misting became obvious after suddenly running straight ULSD on long road trips instead of B100. Refueling with biodiesel fixed our misting problem, so we try to always have at least a little bio in the mix. Fuel mileage is 5-10% lower with higher bio blends (>70%) and power also suffers, so we try to keep it around B50. The car burns very little crankcase oil and starts easily. For the past 150K miles, the cruise control often poops out going up steeper mountain grades, at which point I have to step on the accelerator to remind the car to keep going. Also, a couple of years ago temps went down to 0 F, at which time even B50 caused gelling and jerky performance. Overall, though, the car has been very reliable on biodiesel.
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