Engine
ENGINE & ELECTRICAL
The V6 in the 2006-2008 US (2006-2010 in Canada) market B6 Passat is the 3.6L FSI VR6, engine code BLV. It uses the Bosch MED9 engine management system. In the rest of the world the B6 Passat was offered with a 3.2L version of this engine, with the 3.6 reserved for the high-performance R36 model.
Other versions of this engine have been used in the VW CC, Touareg 3, and US/Chinese B7 Passat; the Audi Q7; the Porsche Cayenne, and the VW Atlas.
While similar in concept to the port-injection 3.2 VR6 used in the MkV R32 and the 8P Audi A3, this engine uses a narrower angle between the cylinders (10.6 degrees) and direct injection, making the head, block, and intake manifold very different. Some accessories such as cold air intakes and exhaust components can be shared between the non-FSI 3.2 and the FSI 3.2 & 3.6.
This engine shares no major components with Audi’s 3.2 FSI V6, as found in the A4, A6, and Q5.
Technical information on the 3.2/3.6 FSI VR6 can be found in
VW SSP 360.
Chips/Tunes
Since there are so few MED9 3.6 VR6s in the US, chip tuning options are limited. United Motorsports, APR, Unitronics, Revo and C2 have all offered programs. Whatever you choose, make sure that the provider of the tune has tested it on the car with the same model intake manifold that you have--the 3.6 in the B6 came with two (see the
Intake section for more info).
Oil Pump Bolt
Some 3.6L VR6 FSI engines came from the factory with improperly installed bolts attaching the oil pump drive sprocket to the block. This bolt could back out, and since the sprocket is driven by the timing chain this could cause the chain to jump time and lead to severe engine damage.
This problem was corrected in the production line for late MY2007 cars and beyond, but if you have a 2006 or 2007 car with a 3.6L VR6 you should assume the bolt is bad and can back out at any time unless you have proof that it has been replaced. Replacement is not difficult but it is labor-intensive due to the bolt’s location. More information can be found in the
Oil Pump Bolt Failure Thread.
Serpentine Belt Tensioner
The 3.6L VR6 uses the same serpentine/accessory belt tensioner as the 3.2L VR6 in the MkV R32/8P Audi A3. This tensioner is known to fail catastrophically by seizing up somewhat commonly in those cars. It has happened to a few B6 forum members but for whatever reason failure doesn’t seem to be as common on the 3.6. Still, it is something that should be inspected at every oil change by checking ease of movement of the tensioner’s roller and using a mechanic’s stethoscope to listen for bearing noise while the tensioner is spinning.
Note that the 3.6 has quite a bit of belt whine from the accessory drive under normal circumstances, and that this noise is not necessarily and indication that the tensioner is bad.
Thread with several experiences of tensioner failure and discussion of replacement
Videos of some failing tensioners in R32s
Replacement DIY from the MkV R32 Forum Note that you need a very short (less than 1.25") triple square bit to do the job in the 3.6 due to the location of the A/C hardline.
Startup Noise
The 3.6 can sometimes make a loud clattering noise for a second or two after a cold start. It appears that hearing this every once in a while, especially if the engine hasn't been started in several days,
is normal. It seems to be caused by the hydraulic lifters, cam adjusters, and/or chain tensioners losing pressure as they sit, leading to noise as they re-pressurize. No damage to the engine has been found to be caused by this. However, if the sound persists for more than 5-10 seconds and happens more frequently, it may mean that
one or more tensioners is no longer holding pressure and needs to be replaced or
there is one or more bad lifter.
Battery
The battery is located in the trunk/hatch area on the driver's (left) rear side. The parts catalogs used by almost everyone in the US are wrong and specify the battery for the base model 2.0T for all B6 Passats. If you have a B6 3.6 4motion, you need a Group 49/size H8 battery rated for at least 760CCA and 92 amp-hours. OEM P/N for an AGM is 4F0 915 105 E or 000 915 105 E; standard lead-acid is 000 915 105 DK-DSP.
High Idle
Some owners experience an elevated idle speed (above 1000rpm), usually in hot weather conditions when the car is under high electrical loads. There is some variation in symptoms and circumstances, but in most cases the cause seems to be excessive electrical resistance, probably caused by a bad ground. A vacuum leak can cause similar symptoms, so both should be checked. More discussion can be found in
this thread.
Some owners have replaced the Crank Position Sensor (G28) to solve this issue. User 4mo_jay has
reported success with this approach.
MAINTENANCE
Timing Chain: VR6 Jedi master
G60ING has put together
a comprehensive thread dedicated to the timing chain system on the 3.6. If you think you hear timing chain noise, or are getting fuel system related codes that don’t make sense, or if you are just interested in learning more about how the 3.6 works,
check out the thread.
Spark Plugs: OEM is usually easiest to find, but some people have had luck with NGK or Bosch,
0.36 gap and heat range 7
Oil: The 3.6 requires an oil compliant with VW 502. Mobil1 0w40 is 502 compliant and easy to find in most auto parts stores, or you can order any of these other oils online:
Audi USA's list of 502-compliant oils available in the US
An older list from the Oil and Lubrication Forum
Changing the oil is relatively simple.
Here's a good post listing all the tools you'll need and some helpful tips.
PCV System: The PCV system is much simpler than in a forced-induction engine. There’s one valve, and while it rarely goes bad according to VW it can only be replaced as part of the valve cover.
There is a trick to blocking off the system temporarily so you can still drive the car until you replace the valve. Fortunately
a BMW tuning company has made a copy of the diaphragm and sells it in Europe for around US$50. You can also
get it in the US from RKX Tech for around US$26. User
dkarolj has
replaced the diaphragm on his valve cover.
I did this on my own car, so I wrote up a DIY with pictures:
DIY: Replacing the Intake Manifold Gaskets, Valve Cover Gasket, and PCV Oil Separator Diaphragm Valve in a 2008+ 3.6 VR6
Valve Cover Torque Specs
Intake Valve Cleaning: Like all direct-injection engines, in the VR6 FSI unburnt fuel builds up on the intake valves causing carbon deposits that can cause the car to run poorly. For whatever reason buildup happens much more slowly in this engine, but you should still plan on cleaning the valves once mileage gets past 100,000-120,000mi.
To DIY you need to remove the intake manifold and it is helpful to get a media blaster and walnut shells to get the heaviest crud off.
Timing Chain Replacement: One thing to remember is that while the oil pump sprocket appears to be round, it is slightly elliptical and
must be aligned correctly in order for the timing to be set properly.
This website has an excellent reference including special tools required, locations of timing marks, and torque values.
Head Gasket: User nater has put together an excellent DIY for 2008 cars with the two-piece manifold. 2007 is similar but removing the one piece manifold will add some extra work.
Head Gasket R&R and DIY 3.6L BLV 2008 Passat
Thermostat Housing (a.k.a. "Crack Pipe"): The thermostat housing is also a junction for 5 different coolant lines and resembles an implement for smoking a certain type of rock. As with older VR6 engines, it's made of plastic. While it isn't as failure-prone in the 3.6 as it was in older designs it can still, well, crack. If it does, or if you need to replace the thermostat, you can replace the housing with a cast aluminum version.
More info, including part numbers for hoses and gaskets you should replace while you're at it, in this thread.
ENGINE REPLACEMENT
Forum member
nater has had a long and unique experience owning a 2008 VR6 4motion since it was new. At 120,000mi he spun a main bearing and chose to replace only the bearing by dropping the oil pan. His conclusion at the time was that the bearing failure was due to low engine oil (and not the "dry start" problem which
may not actually exist). His timing chains became progressively noisier and at 195,000mi he began getting intermittent "Low Oil Pressure/Turn Off Engine" warnings. It turns out one of the timing chain guides had disintegrated, clogged the oil intake, and caused the original bearing failure and subsequent problems. He chose to replace his engine with a remanufactured unit. The entire thread is worth reading for a detailed account of troubleshooting and recovering from catastrophic failure in the 3.6:
I spun a bearing...(now with pics!)
The 3.6 has been used in many different vehicles over the years, and while there are differences they are all pretty much physically compatible. User
G60ING has made a list of
things to look out for when swapping a newer 3.6 VR6 long block into an older 3.6 Passat or Touareg.
2014-03-17: added info regarding replacing the crank position sensor to fix the high idle problem
2014-03-30: added links to lists of VW 502-compliant oils for the US market, and to an oil change DIY
2014-09-09: added section on Nater's bearing failure/engine replacement
2015-07-02: added section on aligning the oil pump sprocket during timing chain replacement
2015-12-14: renamed section to "Engine & Electrical" and added information about the correct size for a replacement battery
2015-12-20: added link to nater' head gasket DIY
2016-02-25: clarified model year ranges for US and Canada
2016-05-09: added info on replacing the PCV diaphragm without having to replace the whole valve cover gasket.
2016-09-27: added link to US supplier for PCV diaphragm.
2016-12-08: added link to PCV diaphragm replacement DIY
2018-03-14: modified section on Startup Noise to include bad hydraulic valve lifters as being a potential cause
2018-08-17: added link to timing chain replacement reference.
2019-05-22: added section linking to G60ING’s timing chain resource thread.
2020-04-23: added info on the metal thermostat housing/"crack pipe" and swapping a newer 3.6 block into an older 3.6 Passat.
