Long-Term Road Tests

Daily updates on our fleet of cars and trucks

2005 Volkswagen Jetta TDI GLS: Fouled Fuel Filter...Again

 

IMG_1894.jpg (The fouled element of our TDI's fuel filter next to a fuel filter we pulled out about six months ago.)

We're wrapping up our test of the 2005 Volkswagen Jetta TDI so we took it to the track for final testing. After doing the acceleration test Chief Road Test Editor Chris Walton told me, "There's a hitch in its get-along. Around 4,000 rpm it hesitates really badly."

I'd felt that hesitation before, about six months after we began running the Jetta on biodiesel (B99). It seems that biodiesel loosens the deposits left in the fuel system from years of running on petrodiesel. The deposits flow into the filter and clog it. I replaced the filter back then and it ran fine -- until last week.

After I wrote about changing the filter the first time, a reader commented that I should cut the old filter apart to see how badly clogged it was. Good idea.

 

IMG_1888.jpg

The only problem was that the filter was made by Germans and it was like trying to break into a bank vault. I have a saw blade for cutting steel golf shafts so I used it to cut the top off the filter. The casing on the filter was made of steel about an eighth inch thick. As I cut into it sparks were shooting all over my garage and burning the hair off my arms. Then, when the blade cut into the diesel-soaked element it started smoking like crazy.

After I evacuated the garage long enough to let the smoke clear, I found that the element slid out neatly. After I shot these pictures I spread out the paper element and tried to feel any grit or residue on it. I can't say that I actually felt anything. But now that the new filter is in there it isn't hesitating anymore so it had to be clogged.

By the way, when I installed the new filter, I could look into the top of it and see the paper elements inside were completely white. After six months of use they are stained black.

The station where I buy my biodiesel puts out a fact sheet and it recommends carrying a spare filter in the trunk just for this problem. The filter I bought cost $43 and took only a few minutes to change.

Philip Reed, Edmunds.com Senior Consumer Advice Editor @ 69,074 miles 

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19 Comments

jfavour says:

10:16 AM, 04/ 6/09

I don't do my own maintenance so forgive me if this is a silly question, but with all of the diesel in the filter, how do you dispose of it? It seems harder and harder to throw things away in regular garbage (which is a good thing imho). I have a garage with many items I am waiting to take to my local county disposal site. Would this fuel filter be another similar item? What do dealership and mechanic shops do with these?

wobbly_ears says:

11:11 AM, 04/ 6/09

The ethanol mafia is pulling the wool over our eyes. Bio-diesel & the 10% Ethanol crap is an indication of how far the lobbying dollars go in Washington. Our cars are being damaged, environment is harmed & massive subsidy is lining the pockets of the very few.

Isn't there a proposal to go from 10% mandatory Ethanol to 20% mandatory? Also, doesn't it bother anyone that it might be unethical to use food grain for fuel?

cruiserhead1 says:

11:53 AM, 04/ 6/09

Phillip,
I am guessing the clog happens at the inlet/exit tubes. Are there check valves inside these just under the lid? My guess is this is where the clog happens.

AMTalker says:

12:26 PM, 04/ 6/09

@Wobbly_ears

Right now the proposal is to allow for up to a 15% blend of ethanol. And there isn't a food shortage as a result of ethanol, corn production was at an all time high last year with still millions and millions of tons of old crop corn sitting in silos ready to be sold at market before billions more are harvested this year.

I won't turn this into a fight, but it might serve you well to understand both sides of an issue.

joefrompa says:

12:26 PM, 04/ 6/09

Wobbly -

Ethanol is not a solution, I agree. But it is a good way to immediately and significantly reduce our reliance on imported petroleum.

A better way of course is to vastly increase our average fuel economy, or reduce the amount used. And ethanol should be made from waste or sugar, and not from actual food.

Bio-Diesel isn't any greener, but it feels good for people to re-use materials. Kinda like the practice of making furniture using some exotic "salvaged" wood from some faraway country, which is far more wasteful and environmentally harmful than using a fast-grown wood product.

Of course, none of those things deals with the question of whether or not a large amount of carbon dioxide in our atmosphere is a positive or negative thing.

opfreakx says:

12:37 PM, 04/ 6/09

joefrompa-

The reason ethanol (at least cornbased) is NOT a soultion is because:

it does NOT significantly reduce our dependance on fossil fuels.

Changing corn to ethanol and getting it in your gas tank, uses roughly the same amount of gas as it saves.

IE it takes (currently) about a gallon of gasoline, to create a gallon of ethanol

wobbly_ears says:

12:53 PM, 04/ 6/09

Do you remember last year when the gas was at 4 dollars & there was severe price spike in Tortillas in Mexico & higher meat & dairy prices here in US? In the case of Mexico, there was even talk of severe social unrest due to the price rise.

Also, isn't it a fact that ethanol isn't as clean burring as regular petroleum? Also, isn't 10% mandate along with massive subsidy is liked only by the corn states & no one else? The taxpayer doesn't like it (subsidies), fuel companies (forced blending), consumers (bad for engines) and environmentalists (not really 'Green')

The middle class is being squeezed at both ends. Higher pump prices & car maintenance costs along with higher taxes due to these subsidies.

AMTalker says:

01:07 PM, 04/ 6/09

I do remember the spike in prices, but those were market driven. Just like the price spike in a barrel of oil. It was outside pressure on the market, speculation. Your argument should be made about a barrel of oil too, not just ethanol.

I would agree that for right now corn based ethanol is not a perfect solution for solving the nation’s energy problems. But the starting point for solutions for all problems are messy. Just think about how much more oil we can get out of a well now than we could 100 years ago when oil production started. The same will happen with ethanol. Right now it is based on corn, the next step will be cellulosic(making ethanol out of the waste in the corn field, corn cobs) then to switchgrass and other plant matter.

And the great debate about energy in/energy out rages on about ethanol. For a long time those studies were flawed and released from pro-oil groups. They said that you had to consider how much energy was used to produce the combine that harvested the corn too see how much energy you could get from ethanol, but they wouldn't do the same for oil. Consider how much energy it takes to build a super tanker and send it across the ocean.

BTW - There are plenty of subsidies for the oil industry too.

texases says:

01:19 PM, 04/ 6/09

Sticking to the biodiesel topic, why do you still think this filter clogged because 'biodiesel's a better solvent'? One filter, maybe, but two?? I doubt it. The simpler explanation is that biodiesel's better at clogging up filters! Also, one has to be very sure of the source for biodiesel before claiming any environmental benefits. The whole fad of biodiesel is responsible for the destruction of large areas of Indonesian rain forest to plant palm oil plantations. Not my idea of a 'green' fuel.

stingray454 says:

01:52 PM, 04/ 6/09

"Bio-Diesel isn't any greener, "

joe - that's not true. B99 or B100 biodiesel contains no sulfur, and thus there are no sulfur dioxide emissions from engines running it, unlike petroleum based diesel. There have also been reports of slightly lower CO and NOx emissions on biodiesel, although it's not a huge difference.

Also, biodiesel can be made from a variety of sources. Waste vegetable oil is one of them, but not the only source. Biodiesel can also be made from a variety of freshly grown plant oils. Either way, I would argue that waste vegetable oil, or new vegetable oil grown from renewable resources such as plants, is greener than consuming a limited natural resource such as petroleum.

opfreakx says:

01:53 PM, 04/ 6/09

AMTalker

Those pro-oil groups talked about how much oil/energy it took to produce both ethanol & oil.

Drilled oil, gives you a huge return on investment in terms of energy.

Corn based ethanol yields almost 0.

Maybe your listening to too much Big-Corn radio.

stingray454 says:

01:57 PM, 04/ 6/09

"The whole fad of biodiesel is responsible for the destruction of large areas of Indonesian rain forest to plant palm oil plantations."

Nooo, irresponsible and negligent Indonesians are responsible for rain forest destruction, not fad of biodiesel (which isn't a fad either). Your comment is similar to the line that "guns kill people." Noooo, stupid people with guns kill people.

The world can have plenty of cost effective biodiesel production without touching a single acre of rainforest.

texases says:

02:06 PM, 04/ 6/09

You might want to read more about the biodiesel mess: http://www.guardian.co.uk/environment/2009/jan/21/network-biofuels

brn says:

03:33 PM, 04/ 6/09

wobbly, when the price of diesel went up 300-400%, the price of farm products did go up. It had nothing to do with the availability of corn, but with the cost of diesel. Farms run on fuel and the delivery infrastructure also runs on diesel. Those costs when up, hence the end price of the product goes up. It's as simple as that.

billt9 says:

05:10 PM, 04/ 6/09

texases,
Any country would cut down their trees to increase human productivity.
We protest about destruction of nature in 3rd world countries, and lobby for their countries to stay heavily forested and have all their land declared wildlife reserves. Screw their people. They should live in the 3rd world and be content with that.

Only America gets to live in the 1st world industrialized computerized society.
We already killed all the Buffaloes and cut down all the trees here centuries ago, so we don't need to do that any more, therefore it's ok for the USA.

It's not ok for the rest of those inferior humans to do the same to their country today. Thats barbaric. It's ok in the 1800s but not in the 2000s. It's too late. It's past the year 2000 now. No one is allowed to change their land anymore. Only smart countries like America who realized all trees and animals had to be chopped and killed in the 1800s can have the good land and productivity.

Phew. Good thing America imposed no land change beyond the 1800s. This way no one can compete with our economic and nuclear weapons superiority.

greenpony says:

07:06 PM, 04/ 6/09

Philip, I bet you never thought this would turn into a political and social discussion, eh? It's just a diesel fuel filter, people.

cwc1 says:

07:14 PM, 04/ 6/09

Billt9, been hating your country long? Ever heard of the right to private property? People take care of things in which they have a stake.

We have tons of trees left. It's a business, so the timber industry plants new trees! Look at how many trees there are along the roadsides and when flying overhead. Millions...

texases says:

07:29 PM, 04/ 6/09

billt9, you make my point by missing it. Indonesia is not at fault for cutting down its forests, we are. We think that mandating biofuels is some majic cure, when it has actually made the problems worse, much worse, in terms of CO2 emissions and fuel use.

brn, you also make the opposite point - if corn went up lots when diesel went up lots, that PROVES that ethanol requires large volumes of oil to make. Corn-based ethanol is no cure, it does nothing for oil conservation and it raises food prices. As one researcher for the UN put it, biofuels, as currently made, are a "crime against humanity".

warren_w says:

08:12 AM, 04/ 7/09

Edmunds must really like to spend extra money. A fuel filter should have only cost $20-$25. Since we're all internet savy, you could easily mail order a filter for much less $$.

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