Don't forget your fuel filter

JASONP · Jul 21, 2010

Just for curiosity sake I took my old filter from my '02 Golf and cut it open to see how bad it was. I had been having stumbling issue under load and bubbles in the clear line and it went away after changing the filter.
well you decide if the pump could get enough fuel. this is approximately 45,000 km's

This is the canister cut open, you can see it is quite dirty.

This is the plate which the filter medium sit on, below that is the water seperator area.

This is the filter medium which is supposed to be white in color not brown poo color.

Another side shot of filter medium

I also replaced the Fuel Temp Sensor which was throwing a code, and when I took it out there was rust on the screws holding it in, guess that means water was getting in there.

T_D_I_POWER · Jul 22, 2010

Nice work.

Which brand FF did you use?

JASONP · Jul 22, 2010

T_D_I_POWER said:
Nice work.

Which brand FF did you use?

Always use OE Bosch for FF, either MANN or MAHLE for OF

naturist · Jul 29, 2010

First symptom (and sufficiently subtle it's easy to miss) of a fuel filter "on the edge" would be stumbling under full throttle. First really noticeable symptom would be loss of power under full throttle to the point of limp mode that recovers once you let off the pedal.

TdiTaff · Jul 30, 2010

I just changed my fuel filter for a Nicktane 1micron, supposedly coming up to 20k miles (according to previous owner). The old OEM filter was black inside, I poured some fuel out to have a look and that was black too.
I didn't have any stumbling at WOT but the car seems to run better now with the Nicktane installed.
Is that totally black fuel/filter normal? The photos posted above seem very clean in comparison!

JASONP · Jul 30, 2010

TdiTaff said:
I just changed my fuel filter for a Nicktane 1micron, supposedly coming up to 20k miles (according to previous owner). The old OEM filter was black inside, I poured some fuel out to have a look and that was black too.
I didn't have any stumbling at WOT but the car seems to run better now with the Nicktane installed.
Is that totally black fuel/filter normal? The photos posted above seem very clean in comparison!

Maybe some algae forming if you ran bio at any point

UFO · Jul 30, 2010

Disgusting how much trash is in the pump diesel fuel. I've never had to replace a fuel filter on a gasoline vehicle.

TdiTaff · Jul 30, 2010

I've never run Bio, not sure if the previous owner did though. I don't think so as he probably would have mentioned it.

TornadoRed · Aug 1, 2010

Microbes can grow in regular diesel, without any biodiesel added. I have never added a biocide, but it might be a good idea at some point, maybe before my next CAT fuel filter swap.

MayorDJQ · Aug 3, 2010

I'd be curious to know how it would have looked at 20k miles instead of 30k.

cardinarky · Aug 4, 2010

UFO: How old are you? In my 50+ years of driving I have seen several fuel filters replaced on my vehicles during that time. I would not want to consider that it was intentionally purchasing bad fuel because we lived in the North then and the diet was usually Marathon, Shell, and Sunoco 94.
A gas filter will last longer than a diesel, usually 40k or 50k miles. But it will eventually plug up.

UFO · Aug 4, 2010

cardinarky said:
UFO: How old are you? In my 50+ years of driving I have seen several fuel filters replaced on my vehicles during that time. I would not want to consider that it was intentionally purchasing bad fuel because we lived in the North then and the diet was usually Marathon, Shell, and Sunoco 94.
A gas filter will last longer than a diesel, usually 40k or 50k miles. But it will eventually plug up.

I've been driving 30 years. Never plugged or replaced a gasoline filter except my track car, which I was upgrading. I've got 190k on my Toyota 4x4, original as far as I know.

But I've plugged filters on all my diesels, and I've been driving diesels for only 7 years now. And two of the filter pluggings were on diesel fuel, not bio, and one was recent at less than the service interval. I still think pump diesel is extremely hit or miss, less reliable than my own filtered bio.

MayorDJQ · Aug 4, 2010

UFO said:
I've got 190k on my Toyota 4x4, original as far as I know.

What engine/year is your Toyota? I had an '89 4wd 5spd 4 cyl 22RE. At about 200k I was getting about 17mpg and was having trouble with it idling after a warm restart. I changed the spark plugs, wires, rotor, dist cap, adjusted the timing, adjusted the valves, but it still wouldn't idle well.

I changed the fuel filter and it was night & day. Right away the idling issues disappeared, it was much peppier, and my highway mileage went up to 24mpg.

UFO · Aug 4, 2010

MayorDJQ said:
What engine/year is your Toyota? I had an '89 4wd 5spd 4 cyl 22RE. At about 200k I was getting about 17mpg and was having trouble with it idling after a warm restart. I changed the spark plugs, wires, rotor, dist cap, adjusted the timing, adjusted the valves, but it still wouldn't idle well.

I changed the fuel filter and it was night & day. Right away the idling issues disappeared, it was much peppier, and my highway mileage went up to 24mpg.

Mine is an '89 with a 22RE as well. I recently took it up in the mountains, and got 30 mpg. It typically gets 26 in mixed city/highway. It's always idled just fine, and if I drove it daily anymore, a fuel filter change would definitely be a priority. I guess I've never got any bad gasoline.

On the other hand my wife was on the road with the 2001 Beetle, about 16k on the fuel filter when it plugged on her, delaying her trip by two days.

DanG144 · Aug 4, 2010

Black color fuel, and thus Filters, is very common in PD engines.

Perhaps because of the high temperatures they have on the return fuel (about 75 C is common), causing asphaltanes to form. Perhaps because the warm fuel grow biologics. Perhaps because the black carbon dust from the brushes on the fuel pump wearing out unbelievably fast causes it to grow.

JKC_NC · Aug 4, 2010

Originally Posted by cardinarky

UFO: How old are you? In my 50+ years of driving I have seen several fuel filters replaced on my vehicles during that time. I would not want to consider that it was intentionally purchasing bad fuel because we lived in the North then and the diet was usually Marathon, Shell, and Sunoco 94.
A gas filter will last longer than a diesel, usually 40k or 50k miles. But it will eventually plug up.

UFO said:
I've been driving 30 years. Never plugged or replaced a gasoline filter except my track car, which I was upgrading. I've got 190k on my Toyota 4x4, original as far as I know.

But I've plugged filters on all my diesels, and I've been driving diesels for only 7 years now. And two of the filter pluggings were on diesel fuel, not bio, and one was recent at less than the service interval. I still think pump diesel is extremely hit or miss, less reliable than my own filtered bio.

Dunno know how relevant...but...my car before my '10 TDI JSW was a '96 Civic...bought new. With an 11 gal tank, I ran that thing to 10.5 gal/fillup for 160000 mi...finally....changing the fuel filter after an oil-change, where the oil-dude mentioned that it had never been changed. The car was running fine. I managed to strip the nuts on the fuel line while changing the filter...ended up costing me ~500 to replace the fuel line / filter / tow from my house where I had originally planned to just replace the filter...I would have been better off just leaving the filter on. I was having no filter-related problems. My point is...I drove the car 160K mi without a filter change with no filter-related problems.

I sold the car @ 180K after getting my JSW. JSW is better build quality...but...the CIVIC did last 180 kmile with only fuel, oil, tires, and one struts job. 5-speed...never replaced the clutch. Did do the belt at 120kmile. really...the Civic was amazingly low maintainance for 13 yrs...and racked up 405 mile per 10.5 gal fill-up week in and out...paid $14000 new after tax.

MacBuckeye · Aug 10, 2010

My 2009 TDI is on it's 3rd fuel filter. The factory filter was in for the first 20K miles. Changed it again at ~27K miles. Going to change it again at 40K miles. No signs of any problems. The "filter plugging" or that black gunk has never appeared. Just the usual water at the bottom of the fuel filter canister. BTW, what is the micron rating of our fuel filters? My limited knowledge of diesel cars and this being my first diesel, I plan to replace the fuel filter more often that I ever did with my gas vehicles. Checking it in between changes is also going to be part of my PM plan. If all goes well, my youngest child will drive this car to HS and college.

Innospec sells a product called Ecoclean that is supposed to help fight/stop filter plugging. I'm not a sales person for them. This is from their site....
ECOCLEAN® High Pressure Fuel Injector Antifoulant is a multifunctional middle distillate fuel additive that recovers lost power, prevents filter plugging, prevents sludging and cleans injectors in newer model-year vehicles operating high pressure fuel injectors.

Prevents formation of black sludge

Prevents filter plugging caused by thermal stressing within the engine

Restores lost horsepower

Reduces exhaust emissions

Provides thermal and oxidative stability

Cleans and prevents deposits formed in high pressure fuel injection systems

Cleans and prevents injector deposits resulting from ULSD

Improves and maintains power

Improves and maintains fuel economy

T_D_I_POWER · Aug 13, 2010

Thx for the info. Good stuff where can you buy this stuff?

I need to do an FFentectomy and see the inside. I've been using the Stanadyne than the PS fuel additives that most TDIers in the forum use.

vschaos · Aug 13, 2010

MacBuckeye said:
My 2009 TDI is on it's 3rd fuel filter. The factory filter was in for the first 20K miles. Changed it again at ~27K miles. Going to change it again at 40K miles. No signs of any problems. The "filter plugging" or that black gunk has never appeared. Just the usual water at the bottom of the fuel filter canister. BTW, what is the micron rating of our fuel filters? My limited knowledge of diesel cars and this being my first diesel, I plan to replace the fuel filter more often that I ever did with my gas vehicles. Checking it in between changes is also going to be part of my PM plan. If all goes well, my youngest child will drive this car to HS and college.

Innospec sells a product called Ecoclean that is supposed to help fight/stop filter plugging. I'm not a sales person for them. This is from their site....
ECOCLEAN® High Pressure Fuel Injector Antifoulant is a multifunctional middle distillate fuel additive that recovers lost power, prevents filter plugging, prevents sludging and cleans injectors in newer model-year vehicles operating high pressure fuel injectors.

Prevents formation of black sludge

Prevents filter plugging caused by thermal stressing within the engine

Restores lost horsepower

Reduces exhaust emissions

Provides thermal and oxidative stability

Cleans and prevents deposits formed in high pressure fuel injection systems

Cleans and prevents injector deposits resulting from ULSD

Improves and maintains power

Improves and maintains fuel economy

Great information. What is the part number for the fuel filter? Any recommendations as to where to buy online? Price? I dont mind changing mine frequently just to be safe.

MayorDJQ · Aug 13, 2010

MacBuckeye said:
Just the usual water at the bottom of the fuel filter canister.

How much water did you find on the two previous changes? I didn't find any noticable quantity at 20k miles. Even in my previous generation TDIs I never found more than a sesame seed sized drop of water.

NewTdi · Aug 17, 2010

I just changed my fuel filter this past week-end at our GTG. I went 100K miles on the filter. I will cut it open and post pictures later this week. Caveat - it is a Cat Fuel Filter which in theory could get upwards of 150K miles or more!

TornadoRed · Aug 17, 2010

NewTdi said:
I just changed my fuel filter this past week-end at our GTG. I went 100K miles on the filter. I will cut it open and post pictures later this week. Caveat - it is a Cat Fuel Filter which in theory could get upwards of 150K miles or more!

I look forward to seeing the photos. From previous photos, the insides of CAT filters look different depending on whether fuel was pushed through by a lift pump (PD engines, mostly), or pulled through by an injection pump. Where the fuel is pushed through, the filter is the same color bottom to top, equally clogged. When the fuel is pulled through, the bottom strip of the filter material clogs up, then the next strip, and so on.

So, assuming you never installed an after-market lift pump, your filter will provide evidence of how long it is safe to go between filter changes. If there is still a "clean" strip at the top, then the filter could have gone even longer. If it is uniformly dirty all the way to the top, then it should have been replaced sooner.

MacBuckeye · Aug 18, 2010

MayorDJQ said:
How much water did you find on the two previous changes? I didn't find any noticable quantity at 20k miles. Even in my previous generation TDIs I never found more than a sesame seed sized drop of water.

I would say about 1-2 tbl spoons. It was rather "gooey" or "clumpy" and had a white tint to it. I will guess and say it had something to do with using Stanadyne. I found a little more water the 2nd time. Never used Stanadyne on the 1st or 2nd filter. I only find the watery junk when I remove the fuel canister. It gets trapped in the bottom. (that's a good thing) I'm sticking with PS, EcoClean, and probably some bio from here on out. Changed fuel filter today along with an oil change. Old FF looked good and will take a peek at the new one in 10K miles.

Ski in NC · Aug 18, 2010

If you find water in your fuel filter drain, even just a bit, there is water in your tank. Much more water, depending on how close the pickup is to the bottom. Water in diesel creates the environment where bio-funk can grow. No water, no funk grows.

So if you are getting crap in your filters, or if you see water at the drain, take the time to clean out your tank bottom.

Never heard of bio growth in gasoline. Only diesel. Gas must be too toxic for the bugs. That's why gasser filters can last so long.

MacBuckeye · Aug 18, 2010

Is checking the tank a lot of work? I read somewhere that checking the lift pump and tank requires a VAG-COM ,removing a seat, etc.. I don't have one. I run my tank almost empty each time and I know people say you can build up condensation (water) that way. I enjoy going 500-600 miles before needing fuel. That's one reason I bought this car. As long as the fuel filter and water separator are working, then all is well.

TDI Power- PM me and I can give you the name of the sales rep so he can locate some product for you.

vschaos- the fuel filter is 1K0-127-434 (Mann Filter) Ask your VW dealer to give you a discount on parts. I get 20% off at the dealer I use. That goes for other Raleigh/Central NC TDI drivers. PM me and I'll hook you up with the discount.

DanG144 · Aug 19, 2010

Removing the lift pump and cleaning the tank takes me about an hour. It might take 2 hours the first time you do it. It is neither physically or technically very challenging.

Some hints and tips are in post #5 here:
A4 fuel pickup assembly removal (same for PD pump and ALH pickup.)

vschaos · Aug 19, 2010

Nothing can be added to get rid of the water in the tank like you can with gasoline? Such as HEET is used....believe all it is anyway is methanol. If not thats fine will just drop tank every now and then if water is found in the fuel filter. Its really hot here in the south all the time...doesnt mean water wont get in the tank though.

MayorDJQ · Aug 19, 2010

vschaos said:
Nothing can be added to get rid of the water in the tank like you can with gasoline? Such as HEET is used....believe all it is anyway is methanol. If not thats fine will just drop tank every now and then if water is found in the fuel filter. Its really hot here in the south all the time...doesnt mean water wont get in the tank though.

Dropping the tank is a lot of work. Running the tank low and opening the fuel pump/sending unit cover is pretty easy. Then just look in with a flashlight. It should be obvious if there's water in the tank because it should accumulate at the lowest point of the tank. If you need to, suck the fuel out with a Mighty Vac or similar type pump.

MyWifesTDI · Aug 19, 2010

vschaos said:
Nothing can be added to get rid of the water in the tank like you can with gasoline? Such as HEET is used....believe all it is anyway is methanol. If not thats fine will just drop tank every now and then if water is found in the fuel filter. Its really hot here in the south all the time...doesnt mean water wont get in the tank though.

I noticed a trace bit of water in the first fuel filter drain/change on our '04 Jetta. I have been using FPPF Fuel Power to remove any residual moisture in the fuel system out of concern for what moisture does to the TDI fuel systems. The main chemical ingredient is ethylene glycol mono butyl ether, a solvent that bonds with water molecules. I have been running this in both of our TDIs for the summer.

http://www.fppf.com/fuelpower.asp

More info:

http://www.fortune3.com/chemstore/Chemicals_A_F-Butyl_Cellosolve.html

MayorDJQ · Aug 19, 2010

MyWifesTDI said:
I noticed a trace bit of water in the first fuel filter drain/change on our '04 Jetta. I have been using FPPF Fuel Power to remove any residual moisture in the fuel system out of concern for what moisture does to the TDI fuel systems. The main chemical ingredient is ethylene glycol mono butyl ether, a solvent that bonds with water molecules. I have been running this in both of our TDIs for the summer.

http://www.fppf.com/fuelpower.asp

More info:

http://www.fortune3.com/chemstore/Chemicals_A_F-Butyl_Cellosolve.html

I read the info blurb on their website, but it's been a long tine since I was in chemslisrltry class. What does it mean to "disperse water". Is the dispersed water going to then go through the IP/HPFP, through the injectors, and out the exhaust?

If that's the case, I'd rather have it collect in the filter or tank where it can be removed.

Don't forget your fuel filter

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