For the 2009, 2010, 2011, or newer Audi A3 or VW Jetta, Golf TDI (common rail engine), see 1000q: 2009-2010 VW TDI and Audi TDI fuel filter change. The procedure and notes are different!
Change the fuel filter every 20,000 miles or as needed. All fuel filters linked from here are made by Mann or Meyle so don't worry about buying a
VW part. In fact, Mann makes the OEM VW/Audi fuel filters. Below
left is a new "Mann brand" Mann filter PU 936/2. The used filter
is an OEM VW/Audi filter 1k0 127 177 a (interchangeable with 1k0 127 434 a) with
the mark PU 936/2
and "Mann Filter".
If you are using high percentages of biodiesel such as 85% or 100% biodiesel, you should expect to change it early since biodiesel will clean out the old buildup and clog the fuel filter if there's significant buildup in the fuel system. Your mileage will vary with biodiesel and the amount of buildup but as a safe rough estimate, change the filter at 1000 miles and then again at 5000 miles after using high percentages of bio. A more economical idea is to install a small clear inline fuel filter before the main fuel filter to screen out larger particles and let you see how clogged the fuel filter may be.
Early symptoms of a clogged fuel filter are stumbling at high RPM or lack of power. A general lack of power could also be limp mode, see 1000q: TDI limp mode and 1000q: can't rev or constant low power for possible causes and the solution. Make sure that these symptoms are not caused by an air leak in the fuel line or a clogged pickup at the fuel tank. Bacterial or algal growth in the fuel tank can clog the pickup. It's also possible that the low pressure in tank electric fuel pump, the lift pump, is failing or bad. This can cause hard starting or a stalled engine due to fuel starvation.
You may hear that the fuel filters are heated but this is a common myth - they are slightly warmed by the return line fuel and ambient heat off the engine. There is no active or electric heater unless someone installed an aftermarket heater for a veggie or grease system. You wouldn't want diesel or biodiesel to be too hot anyways.
One thing I've noticed about the pumpe duse fuel filters is that their filters come out really black. A relativly clean used filter (like on the newer engines) will be brown. The reason why they're so black is because the fuel has a little soot in it. The soot enters the fuel through a slightly leaky injector o-ring. This is considered normal for pumpe duse engines due to the design of the injector. The injectors are separated by the cylinder head and fuel rail by o-rings. These o-rings let a tiny bit of combustion leak by (sooty exhaust gases) which enter the fuel rail. That fuel goes back to the fuel tank and on its way back to the engine, is filtered by the fuel filter. If you take a fuel sample you'll find it's pretty clean but over time, the tiny amount of soot builds up and will turn the filter black.
A related problem is worn injector bores. Any play in the steel fuel injector will wear out the aluminum cylinder head. This lets excess combustion leak by vs. the normal tiny leakage that is considered normal. Symptoms of this problem would include poor running and hard starting because of loss of compression. If your fuel filter is black on a pumpe duse engine, consider it normal unless the engine is experiencing other problems.
There are 3 different fuel filters for 2005.5-2006 VW Jetta TDI. Using your build date and VIN number to find the correct filter is normally correct but you might have an exception during the transition period so check the filter yourself. There are two different types: wide mouth 2 hole and narrow mouth 1 hole. The wide mouth 2 hole had 2 different part numbers depending if your fuel filter housing had a the water bleed screw. This was due to rolling changes and parts availability during production from 2005 to early 2007. My guess is that when they were changing filter styles, the part that was installed on your car was as random as the guy on the assembly line grabbing something from the bin on the left vs. the bin on the right. VW switched from one filter style to the other. When they started making them again in 2009, they switched back to the first one and decided to switch back to the second. Then they decided to use another filter housing and fuel filter on the Audi A3 TDI, even though it uses the same exact engine. In any case, look at the pictures below before ordering a filter.
1. If your fuel filter housing is filter #1 or #2, you should use the wide mouth "2 hole" filter (they are interchangeable). The physical differences are the star shaped cap on #1 and #2 vs. the wide lip cap on #3. #1 has a bleed screw in the middle of the cap and the others don't. #1 also has a bayonet clamp so you can remove the housing by pulling it up and out. The others are secured to the motor mount by 3x 10mm bolts/nut.filter #1: use VW# 1k0 127 434. The service manual says that some fuel should be drawn out of the torx screw drain but you will probably never find water. (The drain pulls from the bottom of the housing) The other filter types don't even have drains.
2. If your fuel filter housing is picture #3, use VW#1k0 127 434 b, from kermatdi
Housing picture number #1 and #2 use A or the no suffix filter. #3 only uses filter with suffix B. If the first 2 digits of the last 6 VIN digits are higher than 83 or very low like 00 or 01, you most likely use the narrow mouth "1 hole" filter. Sometime in 2006, they ran out of VIN numbers and started back at 00. If the car was built between 1/2005-4/2006, it probably uses the A or no suffix filter.
Most "special editions/diesel editions" use the narrow mouth "1 hole" filter. To see the differences in 2005.5, 2006, and 2006 special editions, see 1000q: a5 early TDI buying guide. Some late 2006 cars are reported to be missing the diesel edition emblems because it was removed so look for the other signs.
The internal difference is in the filter height and internal construction. The wide mouth filter sits higher to make space for the water separator and
the narrow filter does not. You'll probably never find any water in the
The filter housing with the bleed screw was disassembled to show the path the
fuel takes inside the housing by DanG144 and is mirrored here with permission (thanks!). Click the thumbnail image to open his .pdf file in a new
Parts (click links to compare current prices, some prices include shipping)
T30 torx screwdriver/wrench bit
rags or paper towels
1 VW fuel filter, see the notes above to confirm which filter version you need or,
20k mile filter kits (includes other misc filters, must include VIN when ordering to confirm correct fuel filter) kermatdi early A5 jetta, kermatdi later A5 jetta, metalman parts kit
Safety disclaimer - you are working with open fuel lines and fuel vapors
when you change the fuel filter! Make sure that there are no sources of
ignition, spark, or open flames near the car or where fuel vapors could reach.
Work only in a well ventilated area where any fuel vapors can be immediately
evacuated and if fuel is spilled, clean it up before you continue working.
Although diesel vapors are not as flammable as gasoline vapors at room
temperature and pressure (as seen in the
video below at the 1:00 minute mark - it's a demonstration only, do not try
that yourself!), you still want to comply with all cautions in your factory
service manual. Wear eye protection at all times when working on your car.
See the TOS Agreement for the full legal disclaimer. Diesel fuel will melt
asphalt and rubber lines on your car so clean up any spills immediately.
Make sure to use gloves because diesel fuel has a strong odor and you don't want
it soaked into your hands.
The key should be off and the engine should not be running. Wrap some rags around the filter housing to soak up any fuel. Some diesel fuel will spill out and it's bad for asphalt and rubber parts. Here is a video showing the basics, please read all the notes here as well and ask any questions in the forum.
There are 5 T30 torx screws holding the filter housing and 1 torx screw for the bleed point in the middle. Loosen the bleed screw to help release any pressure and then remove all 5 torx screws to remove the cover. If your fuel filter doesn't have a bleed point then ignore that part. If the torx screws are tight, don't risk stripping them. Put a drop of PB blaster or other penetrating lubricant around the screw heads and tap the screw to let it penetrate for a while. Then try again. Their torque is only about 2 ft-lbs so it's common to have overtightened screws.
Some fuel will splash out when you remove the top. Wipe up any spills.
The green seal that came with the new filter is for the housing cover. The blue "olympic
rings" seal is for the fuel filter. If you have a bleed screw there's
also a metal washer under the screw. If you don't have a bleed screw
ignore the metal washer that came with the filter. If you have a
narrow mouth "1 hole" filter, there is only an o-ring.
The top part (the cap) has fuel lines connected to it. The bottom part is the canister. Some have tabs as shown below (pull them towards the up and towards the rear of the car, yellow arrow below) holding it down and some have 2x 10mm bolts and a nut (also visible below) holding it down. If you have to loosen the bolts, the left one only has to be loosened because the filter housing has a gap to allow it to move. The middle one has to be removed. The nut also has to be removed.
Remove the canister as shown in the video. Pour the old fuel into the tank and clean it out.
The tabs fit into these slots on the fuel filter bracket (removed for
illustration). The style with the tabs is slightly different in that the left bolt has to be removed to remove the bracket. If you have the other style canister than the left bolt has to only be loosened because the bracket has an opening when it will slip out.
Slowly pry the old filter straight up with two flat screwdrivers. It's
clamped down and pulling it by hand usually results in the filter popping out and fuel
spilling everywhere. Always wear eye protection at all times when working on
If you have a narrow mouth filter, it's closed on one end so there's no
column on the inside. Remove the old filter and replace.
Slowly push the new filter into the fuel filter housing. If you push quickly, it will squirt fuel out of the bottom of the housing. This is another reason to remove and clean the old housing. Make sure it is seated all the way down.
Fill the housing with clean diesel fuel or diesel purge fuel additive as much as possible. Diesel fuel is a lubricant and you want to have as little air as possible in the fuel system injectors and pumps.
Replace the blue "olympic rings" and green filter cap seal. The blue "olympic rings" fuel filter seals will only fit into the recessed
housing one way. There is also a tab on the column which aligns the
cap to the column.
Hand tighten the T30 torx screws hand tight in a star pattern, much like you would tighten wheel lug nuts. This method will help avoid pinching the o-rings and causing a leak.
If you have an early filter with the bleed screw, check that the bleed screw on the top and the 5 torx
screws are tightened properly to 2.2 ft- lbs. This is 27 inch lbs or 3 NM.
If you have a later filter with no bleed screw, tighten the T30 torx bolts to 3.7
ft lbs, or 44 inch lbs, 5NM. I don't know why the service manual states
different torque settings for different filters so just don't overtighten the
Turn the ignition key to the "ON" position without starting it for a few seconds. Turn the key all the way to off, then back on to ON. Repeat a few times. This lets the electric fuel pump in the fuel tank prime the filter and fuel lines. The fuel pump automatically shuts off after a few seconds even if it doesn't encounter resistance so repeat as needed and the car should start. Although you filled the fuel filter canister with fuel after replacing the filter, you still want to purge the line or pressurize them.
Replace all the clamps and check for any loose tools. Take a test drive and check for any leaks.
If you had to remove any of the fuel lines, here is a picture showing routing.
How did the DIY fuel filter replacement on your 2005 or 2006 VW Jetta TDI go? Feel free to share your experience in the myturbodiesel.com forums