3.6L VR6 BLV Engine Rebuild Information and Parts List
Updated: Feb 16
Since having started the re-build process of the VR6 engine going into the Mk1 Rabbit, I've noticed something interesting: the large 3.6L version of the 24v VR6 engines is quite a bit less popular than the older 12v and 2.8/3.2L 24v VR6 engines. Sure, they are newer engines, but having been available in Volkswagen passenger cars for more than 10 years so far, it was quite easy find ours at the local Pull-A-Part for $240 with accessories, which is a steal for a compact 6-cylinder engine with 276 naturally aspirated horsepower.
As a result, it was quite difficult to price together an affordable full-rebuild, with many aftermarket companies only offering certain parts/seals and not others.It was especially difficult finding aftermarket piston rings, as the 89 mm pistons were not shared with any other VR6 engine. There were no-name eBay listings imported from China, however I stayed away from those for obvious reasons. OEM rings were $163 per piston. However I did it, and here are the details below:
Rotating Assembly and Block :
Main Bearing Set: King AM-Series Main Bearings MB7089AM, $82.99 x1
Piston Ring Set: DNJ Standard Size, $67.99 x1
Main Bearing Cap Bolt: VAG OEM N90365801, $2.81 x 14
Timing Chain Components :
Timing Chain Tensioner Piston: INA on Rock Auto, $19.51 x1
Upper Pivot Guide: VAG OEM 03H109509A, $31.00 x1
Slide Rail: VAG OEM 03H109513B, $26.32 x1
Head Gasket: Reinz 03H103383K, $47.43 x1
Head Bolt M9x1.5x141mm: VAG OEM WHT005466, $1.33 x7
Head Bolt M9x1.5x111mm: VAG OEM WHT005465, $1.42 x13
Gaskets and Seals :
Head Gasket: Reinz 03H103383K, $47.43 x1
Front Main Seal: National 710618, $7.45 x1
Rear Main Seal: Corteco 20027584B, $14.43 x1
Oil Pan Level Sensor O-Ring: VAG OEM 038103196, $6.23 x1
Plastic Coolant Pipe to Engine Block Water Pump: VAG OEM WHT005190, $5.09, x1
Plastic Coolant Pipe to Coolant Elbow O-Ring: VAG OEM 03H121041, $7.19 x1
Coolant Elbow O-Ring to Cylinder Head: VAG OEM 03H121041A, $1.57 x1
Oil Filter Housing to Engine Block O-Ring: Reinz 066115111A, $2.09 x2
Other Parts You Probably Should Buy :
Oil Pan Bolt: VAG OEM N10404404, $1.16 x1 - Note: says it does not fit but it does
Thermostat Housing & O-Ring: REIN CTN0025, $36.79 x1
Serpentine Belt Tensioner: Aftermarket 022145299L, $21.68, x1
Spark Plugs: BOSCH 7431 OE Fine Wire Double Iridium, $6.47, x6
Air Filter: Hengst 1K0129620, $7.85, x1
Oil Filter: VAG OEM 070115562 w/ Gasket, $10.03, x1
From left to right: connecting rod (cap side), connecting rod (rod side), main bearing (cap side), main bearing (block side).
Plastic timing chain guide, definitely time for replacement. The timing chains looked normal, and I will not replace them unless they throw a cam timing code.
Oil pump. Upon initial disassembly, it looks great, but....
This is the journal in the aluminum oil pump housing. As you can see, there appears to be a hardened coating that has galled and chipped away completely, and there is a groove where the inside planetary gear rubbed against the housing. Garbage.
Other things I noticed
As for ring wear, there was no significant vertical scoring in the bores, however we noticed a pretty significant lip near the deck of the block. You could still see some of the cross-hatching, but in order to remove the lip you would probably need to bore the engine out 0.030" and install larger pistons and rings, a very expensive addition to an already rather expensive rebuild. One person that I talked to said they've never seen a VR6 without this lip, and so I decided to keep the existing rings and not do an overbore. Something to note on VR6 engines, is that the axis of the bore is not perpendicular to the deck, but the piston is asymmetrical and the piston top is perpendicular to the deck.
The connecting rod bearings (in particular, the rod side) showed the most wear, and were the only bearings that showed deep scoring from particulates. In reality, these bearings aren't the worst I've seen and would probably hold oil pressure fine for another 100k miles. The crank journals looked perfect and I did not touch them up.
The thermostat is this thing made up of a large heavy spring and plastic. The design is such that three small plastic tabs hold the spring pressure when removed from the engine, and these break off when you remove the old thermostat from the engine. You will need a new one.
The main bearing cap bolts need to be replaced as they are torque-to-yield (TTY). One of the old bolts measured 79.22 mm, meaning it permanently stretched 1.22 mm longer compared to the new 78 mm bolts.
Torque Specs / Sequence and Bearing Clearances
Unfortunately this information is hard to come by as this engine is quite uncommon. VW somehow managed to create a torque spec guide for the 2007 Passat, yet forgot to include torque sequences for the main caps and cylinder head. The bolts listed as always replace are torque to yield. Unlike traditional rod studs, changing the bolts these connecting rods does not require an align hone.
I could not find torque sequences for the main caps, and so I followed what is normally done on 15 degree 24v 3.2 VR6s, which is to start in the middle and work your way to the outside. Torque to 30 Nm (22.13 ft-lbs), and then check that the crank rotates freely. Then do the 1/2 turn and recheck the crank rotation. I used a paint pen to mark each bolt when I reached the desired torque, and to make sure I did not miss one.
Final Thoughts and Considerations
One thing to note is that not every part you could possibly replace in a rebuild is listed above; these are the parts I personally needed to take a Pull-A-Part engine with about 181K miles on it and rebuild it to be a reliable engine in my 1981 Mk1 VW Rabbit. One thing you may notice missing is the timing chains. Timing chains will not outright break, rather they will stretch over their life, and the end result is that the ECU will pick up that the cam timing is slightly off, and this will throw a code. VW's policy is to replace timing chain components on this engine when a code appears, as these chains are "supposed" to be lifetime for this engine. I decided not to replace these right away as no codes are showing up, but you may want to consider this if you have a larger budget.
Thats it for now, I will update this post as the Rabbit build further progresses.