back to 1000q: 2004 2005 VQ Passat TDI DIY index and FAQ
While the 2004-2005 Passat sedan and wagon TDI are close in size to a mk5 A5 Jetta sedan and wagon, the driving feel is not the same. The car is heavier, bigger, and uses a multi link front suspension. Compared to the Jetta sedan/wagon, the Passat drives smoother over the bumps in the road because of suspension tuning and the suspension layout. Combined with the extra engineering time and work spent refining noise, vibration, and harshness, it's significantly quieter than a mk4 or mk5 VW Golf or Jetta. And although the size is about the same, the Passat wagon has a more square rear vs. the Jetta wagon's rounded rear which results in a little bit more usable room.
The downside is that average fuel economy is lower because they were only sold in automatic "tiptronic" transmission in North America and they are heavier, bigger cars. All Passat TDI in North America are front wheel drive. No 4motion AWD was available with the TDI engine and it's not possible to convert your TDI to 4motion because of the floorpan. It would be possible to covert a 4motion to TDI.
You may see B5 - this refers to the 5th generation of B-chassis car, the 1998-2005 VW Passat. All B5/B5.5 are mark4/mkiv/mk4 cars, the 4th generation of VW. All TDI (2004-2005) are technically B5.5. The late B5.5 (all TDI) got many upgrades such as round aero side view mirrors w/turn signals, new projector headlights, bumpers/taillights, fenders, chassis and suspension refinements, and interior differences. Many B5 parts will work on your B5.5.
B5 also refers to the 1996-2001 Audi A4. Many mechanical parts on your Passat like the front suspension are the same or interchangeable with the parts used on the Audi A4 and Audi A6 of a similar generation.
There were no B6 (2007- present) Passat TDI sold in North America, only Europe and some other areas. There were station wagons sold in North America but they were gas engines only. The new VW Passat TDI (2012+) is sedan only. There is no VW Passat station wagon planned for North America for 2013, 2014, or the forseeable future. There is a wagon sold in Europe but it's the Euro Passat, not the NA passat.
A full list of "how to" for the 04-05 Passat is linked above. General technical TDI FAQ and information can be found at 1000q: FAQ and "how to", the blue button at the upper right. Also feel free to sign up and ask any questions in the VW Passat TDI general forums linked at the top blue buttons and here: myturbodiesel.com
Most auto parts stores give free error code scans. Not every error code will set the check engine light (CEL) or malfunction indicator light (MIL). If you do DIY maintenance, buy a VW/Audi specific VCDS car diagnostic cable and software. It has lots of diagnostic features and support modes that are not available through a generic OBD2 code scanner. Does the car run poorly, is slow, or suddenly loses power? See 1000q: constant low power and 1000q: sudden limp mode diagnosis.
Bad oil pump and oil pump failures is a very common problem on the VW Passat TDI. This problem is also found on European VW and Audi that used a similar engine. A bad oil pump chain sounds like a rattling loose blender. Failure will cause loss of oil pressure and serious engine damage. The replacement oil pump is gear driven instead of chain driven and was installed on engines in Europe mid-2006 and later. The mileage at which 2004-2005 VW Passat TDI are having this problem varies greatly and I strongly suggest having this proactive repair done to avoid any problems. When the oil pump fails it's already too late to prevent additional damage since you'll see low pressure for a while before the warning light goes off. The timing belt replacement should be done at the same time. See 1000q: oil pump FAQ for background technical information and 1000q: balance shaft/oil pump replacement - part 1 for the repair procedure.
= 80,000 change (from VW's official site). There is some confusion why since other similar engines have 100,000 mile changes. My owner's handbook even says to change it at 90,000 and again at 100,000! You should also change the tensioner, rollers, and water pump. See 1000q: BHW Passat TDI timing belt change for more details. If this part fails, the cylinder head will be damaged and in severe cases the car will need a new engine. All TDI are interference engines. If the timing belt or associated part fails, the valves will hit the pistons and cause severe engine damage. If you have any doubt about the condition of the timing belt, have it changed as soon as possible not as soon as practical!
= 10,000 mile change w/filter if you are using synthetic engine oil for compression engines (TDI). See 1000q: pumpe duse engine oil for a list of oils approved by VW for pumpe duse engines. Generally speaking, long oil change intervals are good for the engine assuming that you use the correct engine oil. It's normal for the oil to be black, even when new. See 1000q: Passat TDI engine oil change for the procedure.
- Look under the front/lower engine bay. You should see a plastic splash shield - it covers the bottom of the engine bay. If you can see the engine or see the ground looking down through the engine bay, it should be replaced. It keeps water and dirt off the bottom of the engine and belts. If you see a metal shield, someone upgraded the plastic shield to protect the aluminum oil pan (article is for a Jetta but same general idea). If you're missing parts on the shield, see 1000q: splash shield parts list.
Tire air pressure = as specified by the manufacturer. There is a sticker inside the fuel door, on the inside of the driver's side door, or in the trunk which will specify an appropriate cold tire air pressure. Check tire pressure when the tire is cool or you haven't driven the car in at least 5 hours. A generic tire pressure for an average weight passenger car is 32 psi. Never exceed the cold tire pressure listed on the side of the tire.
Engine coolant = the coolant should be changed as necessary. VW/Audi G12 (G12+) or Pentosin coolant is red, pink, or light purple. Do not mix G12 with other colors (green, blue, orange) or else it will sludge the coolant. If it has to be topped off, use distilled water. If you are topping it off more than once, first figure out where the coolant is disappearing. See 1000q: coolant flush or change for more details and pictures.
= 10,000 mile drain water, 20,000 mile replacement. If you plan on using high percentages of biodiesel, you should change it as soon as practical because biodiesel can loosen up deposits. See 1000q: Passat TDI fuel filter change for more details. See 1000q: intro to biodiesel for more info on biodiesel.
Coolant migration = This is a rare but serious and bizarre problem where coolant travels through the wiring harness due to defective coolant tanks. This will damage all the wires and electrical components. This could total the car because in extreme cases, coolant can seep all the way back to the taillights and corrode all the electrical contacts! See 1000q: coolant migration for more details. It only takes 5 seconds to check and is a rare condition. It is more common on Jetta/Golf/New Beetle but some Passat have had it.
Tandem pump leaks - The tandem pump is a dual fuel and vacuum pump on the rear of the cylinder head. It pressurizes fuel and provides vacuum for the brake booster. If diesel fuel leaks onto the various rubber hoses, it can melt them.
Engine runaway - All diesel engines could have an engine runaway because of a mechanical malfunction which causes the engine to race high by itself and self-destruct. This is because diesel engines can run off engine oil and are throttled by fuel. If this ever happens, keep control of the car and shut off the ignition as soon as is practical and safe. Don't restart the engine. Don't risk getting into an accident to save the engine. Take it to a mechanic before starting it again. Read more about diesel runaway at 1000q: runaway engine FAQ. Your TDI has an electronic shut off valve that is stronger than earlier vacuum operated valves which should stop a runaway engine.
VW switched to ceramic glow plugs in all of their TDI in 2004. Some broke which sent metal into the engine, causing major damage. However, the new ECU program which is required for the steel glow plugs doesn't work well and caused cold start problems in near freezing or below temperatures. VW has since fixed this with another recall. See 1000q: glow plug recall related cold start problem FAQ for more details. See 1000q: glow plug for more details on the glow plugs.
There are water drains under the brake booster/master cylinder (next to the battery), around the windshield base under the battery, and at the corners of the sunroof. If leaves, mouse nests, or debris clog the drains, water will build up and leak into the interior. This can damage the convenience/comfort control module (CCM), automatic transmission computer, and a number of grounds. Symptoms include transmission limp mode or the window, alarm, or remote key fob not working. Use a hose to keep them clean. You can use compressed air to blow leaves out of the engine compartment. Also remember to close the windows when it's raining. See this article for pictures of the sunroof drains: 1000q: sunroof drain cleaning. VW finally made this inspection official by adding an owner's manual supplement that calls for an inspection and/or cleaning every 2 years or 40,000 miles, whichever is sooner.
All pumpe duse TDI should have a camshaft inspection. General mechanics wouldn't know about this so it's not included in the immediate checks. It's also not something easily done during a pre buying inspection. Some camshafts have worn down their lobes and caved in the lifters because of wear. The surface of the hydraulic lifters should be smooth with no major scratches (super fine scratches that you can see but can't feel are normal). If the car runs fine, remove the valve cover and inspect the camshaft before your next timing belt job to see if it needs to be replaced. Some believe that ZDDP zinc engine oil additive could prevent further wear. See 1000q: VW TDI worn camshaft lobe check for the detailed procedure.
See 1000q: direct injection vs. pumpe duse vs common rail for detailed descriptions of what pumpe duse is. Also read 1000q: proper engine break in for proper engine break in and why put the engine under high load/rpm is good for an engine.
The light for the climate control knobs often burns out. Just pull out the center knob straight out to replace the light bulb. The knob and bulb are shown on a Jetta (same thing) to the right.
Check the motor mounts for leaking. They are hydraulic filled and will leak red fluid out the bottom if they are bad. VW/Audi has since redesigned the motor mounts to be more durable. The engine won't fall down but excess shaking and vibration isn't good for the driveline and comfort. See 1000q: change motor mount for more details on how to replace them and examples of leaking mounts. If you have shaking at idle when stopped that goes away when you put the car in neutral, your CV joints are probably bad. See the next link for details.
If you see grease splattered around the inside of the front wheels, the outer CV boot is torn and leaking. Replace it to prevent joint damage. See 1000q: CV boot repair for the procedure.
The CCV (crankcase ventilation) hose leaks at the bottom because oil mist condenses there and there's only a barb holding the hose on. With the engine cover off, look at the valve cover breather hose. Follow it down: the bottom may be dirty and wet from a leak. A smear of gasket maker and a clamp will stop any leaks there and keep the entire lower engine area much cleaner. See 1000q: air filter box removal for pictures.
Always use the parking brake when parking! This is good practice with any car but especially important on VW/Audi because the parking brake sets the rear caliper self adjusters. You can also jack up a rear wheel and spin it to check for dragging parking brakes. Minor contact and scraping is normal but any drag means the parking brake or calipers need adjusting. If you smell hot and burning brakes then the rear caliper could be stuck.
One of your wheel lug bolts (per wheel) may have a star pattern head instead of a 6 sided hex head. This is an anti theft lug nut. The key is in the small pouch in the tool kit lid. Look in the trunk by the spare tire or on the left/right trunk storage panels. VW stopped using these so switching to a regular lug bolt is an option if you're not worried about someone stealing your wheels.
Don't leave the power mirror selector in the center position because this position is "heat". This is shown in the picture to the right. Most people leave it in the center position and it burns out the heating element in the side view mirrors. VW finally changed this design issue in newer models by linking it to the rear defroster or a temperature sensor. In this case the middle position is a "0". See 1000q: power mirror glass replacement to remove the mirror glass and heater element.
You may want to install a metal skidplate to replace the plastic splash shield. The oil pan is aluminum and it will crack if you bottom out the oil pan on a speedbump, pothole, or if a tow truck's yoke (the metal bars that lift the wheels) hits it. If you hit something and see the STOP - low oil pressure warning come on, pull over and shut off the engine as soon as is practical and safe. Don't risk getting into an accident while you pull over. Check for oil leaks and the oil level.
A worn out suspension can make the car more likely to bottom out. A suspension overhaul every 100,000 miles or as needed will make the car feel like new. The suggested replacement parts are the control arms (they have built in bushings and ball joints), front sway bar bushings, and front/rear shocks. See 1000q: control arm replacement and 1000q: sway bar bushing replacement for more details. The car uses the same front suspension as an Audi A4 or A6.
If the doors, alarm, or interior light don't seem to know that you opened the door, it's because the door module microswitch has failed. Because of use, it's normally the driver's door. To replace, see 1000q: door module replacement. Common symptoms include the door/alarm going off even after you open the door or the driver's side door not setting off the interior lighting but the passenger side does.
The AC relay tends to fail. It's relay 384.
A recommended chip tuners who specalizes in TDI engines is KermaTDI. TDI engines are very responsive to chip tuning because they are turbo and have good power potential. The BHW engine is similar to same generation engines found in the Jetta-Golf-New Beetle TDI but is slightly different because it already comes with more power than the other models. There are more advanced power upgrades available like larger turbos but chip tuning is a good first start. The transmission has no problem handling the extra power.
There were 2 trim levels, GL and GLS. The GLS added alloy wheels, homelink (garage or other remote control), leatherette interior, foglights, the monsoon radio, heated seats, and a sunroof. There may have been a few GLS without a sunroof or ESP but almost all have these. OnStar was also a rare option.
You can tell if a car has heated seats if it has the heated seat controls (upper white arrow in the picture below).
A car has the monsoon radio if it says monsoon on the tape cassette cover (yellow arrow below). This adds an amp and different speakers. The 6 CD changer is separate.
The wood and leather package shown in the example below added a leather multifunction steering wheel (MFSW, the buttons on the steering wheel seen below) which control the radio volume/station and cruise control. It also added leather door cards (the interior panels), seats, armrest, and wood trim to the center console, door handles, shifter knob, and ashtray.
mk5 Jetta/Golf wheels will fit but will have a lot of tuck-in because the offset is wrong (around et50). B5 were around 45 but B5.5 wheels are around 37 so look for wheels around that.
Although most Passat TDI have leatherette upholstery, there are a few rare ones with cloth interiors. (If you wish to change the interior, see 1000q: door panel removal and 1000q: front seat removal. The rear seats are very easy to change as well.) Leather has a solid surface and leatherette is perforated. Leather is softer and more flexible in cold weather but can dry and crack without care and conditioning. Leatherette is more durable and maintenance free but needs the perforated surface for breathability and gets harder in cold weather. In the picture below you can see solid leather on the front seat. If the entire seat is like that it's leather. If some of the seat surface is perforated it's leatherette.
The button (lower white arrow) in the picture below will say either ASR or
ESP. ASR anti slip regulation is traction control only. This brakes
a slipping wheel during low speeds only to
help you get traction (like trying to move from a stop on ice). ESP is
stability and traction control. It uses a steering wheel sensor, different
ABS pump, and yaw sensor to cycle all 4 brakes to help straighten the car
if you lose control (like swerving the car too much at highway speeds).
Because stability control works by reducing power and braking, once you exceed
the tire limits no stability control can defy physics because a tire has a
traction limit. An example of exceeding traction limits is driving on
solid ice with summer tires (they get hard and lose traction as they get cold).
The coefficient of drag is .27 for the sedan and wagon which is excellent to the point of mentioning it as a feature. By comparison, the same year VW Golf was .31. The VW Touareg SUV was .38. The Prius is .25.......
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That's all the most common notes with the Volkswagen Passat TDI, see 1000q: mk4 VW Passat TDI "how to" index for a list of how to. If you know of something else that should be added to this article please post your comment in the myturbodiesel.com VW TDI forums You can also search the site here: